Chemistry

Fe Electron Configuration – Properties

Iron mineral

Other than being usually found on Earth, it is copious in the sun and stars, as per the Los Alamos National Laboratory. Iron is significant to the survival of living beings, as per Jefferson Lab. In plants, it assumes a job in the generation of chlorophyll. In creatures, it is a segment of haemoglobin — a protein in blood that conveys oxygen from the lungs to the tissues in the body.

90% of all metal that is refined nowadays is iron, as indicated by the Royal Society of Chemistry. A large portion of it is utilized to make steel — a combination of iron and carbon — which is thus utilized in assembling and structural building, for example, to make strengthened cement. Hardened steel, which contains in any event 10.5 per cent chromium, is very impervious to consumption. It is utilized in kitchen cutlery, apparatuses and cookware, for example, hardened steel dish and skillets. The expansion of different components can give steel other valuable characteristics. For example, nickel expands its solidness and makes it progressively impervious to warmth and acids; manganese makes it increasingly sturdy, though tungsten causes it to keep up hardness at high temperatures, as per Jefferson Lab.

Here are some facts about Iron

• Nuclear (number of protons in the core): 26

• Nuclear image (on the Periodic Table of Elements): Fe

• Nuclear weight (normal mass of the molecule): 55.845

• Thickness: 7.874 grams per cubic centimetre

• State at room temperature: Solid

• Dissolving point: 2,800.4 degrees Fahrenheit (1,538 degrees Celsius)

• Breaking point: 5,181.8 F (2,861 C)

• Number of isotopes (atoms of a similar component with an alternate number of neutrons): (incorporate what number of are steady isotopes): 33 Stable isotopes: 4.

• Most basic isotopes: Iron-56 (regular bounty: 91.754 per cent

• Blood is red as a result of the association among iron and oxygen, as per the blood looks red on account of the manner by which the substance bonds between the two components reflect light.

• Pure iron is in reality delicate and pliable,

• In 2007, specialists found a gigantic crest of iron-rich water emanating from aqueous vents in the southern Atlantic Ocean.

• Iron is fundamental for the development of phytoplankton — little marine microbes that utilization carbon dioxide from the air to fuel photosynthesis. A few specialists have along these lines contended that treating the seas with additional iron could help suck up abundance carbon dioxide. In any case, an examination distributed online in November 2010 in the Proceedings of the National Academy of Sciences found this probably won’t be such a smart thought, as this additional iron could really trigger the development of poison creating green growth that add to the pollution of marine untamed life.

• About 90 per cent of all metal that is distilled today is iron.

• Iron is a significant segment of a shooting star class known as siderites,

• An iron column dating to about A.D. 400 still stands today in Delhi, India, as per. The column is about 23.75 feet (7.25 meters) high and measures 15.75 inches (40 centimetres) in distance across. Regardless of being presented to climate conditions, the column has not consumed much because of its remarkable piece of metals.

• Examples of iron-rich substance incorporate meat, for example, hamburger, turkey, chicken and pork; fish, for example, shrimp, molluscs, shellfish and fish; vegetables, for example, spinach, peas, broccoli, sweet potatoes and string beans; bread and grains, for example, grain oats, entire wheat bread and advanced rice; different nourishments, for example, beans, lentils, tomato glue, tofu and molasses,

• The surface of Mars is red because of a lot of iron oxide (rust) on its surface, Mars has more than twice as much iron oxide in its outside than Earth.

• Earth’s strong internal and fluid external centres are fundamentally made out of iron (around 85 per cent and 80 per cent by weight, separately). The electric flow produced by the fluid iron makes the attractive field securing Earth, as per NASA. Iron is likewise found in the centres of the majority of the planets in the Solar System.

• Iron is the heaviest component framed in the centres of stars, as indicated by JPL. Components heavier than iron must be made when high mass stars detonate.

• The Latin name for iron is ferrum, which is the wellspring of its nuclear image, Fe.

• The word iron is perhaps gotten from before words signifying “heavenly metal” since it was utilized to make the swords utilized in the Crusades.

Electronic Configuration of Iron

Iron is a substance component with a nuclear number 26. It is the most well-known component that is found on the earth. In contrast to that of different components, iron exists at oxidation conditions of – 2 to +6. Basic iron happens in a low-oxygen condition despite the fact that it is receptive to water and oxygen.

Iron is portrayed by the capacity to shape variable oxidation expresses that vary in a couple organometallic sciences. Since iron is accessible in bounty in nature, it is some of the time named as a model for the whole square of a change metal. Ferric is the iron mixes, and ferrous is the iron mixes.

Mixes of iron are fundamentally shaped at +2 and +3 oxidation states. They may likewise happen at higher oxidation state + 6. One of the incredible models would be potassium ferrate. In a different biochemical oxidation response, Iron goes about as a middle of the road. Iron can’t achieve an oxidation condition of +8, and it is one of the primary components of its gathering.
Iron does not have 8 valence electrons, it just has 2, here’s the reason.

Oxidation state relies on the valence electrons and valence electrons are the electrons present in the external most shell of an ion

For Fe, n=4, N shell,

In Iron the electronic setup of Fe = 1s2 2s2 2p6 3s2 3p6 4s2 3d6 from the electronic setup and the beneath graph you may have an unmistakable thought regarding valence electrons in the Fe i.e., Iron has just 2 valence electrons.

For Fe when two 4s electrons are expelled, it has a +2-oxidation state and electronic arrangement of Fe+2 = 1s2 2s2 2p6 3s2 3p6 3d6

Presently, the n=3 turns into the external most shell, iron can lose electrons from this shell also more explicitly from the 3d subshell which has 6 electrons. When one electron from 3d subshell s expelled, iron has a +3-oxidation state and electronic arrangement of Fe+3 = 1s2 2s2 2p6 3s2 3p6 3d5 +2 and +3 are the normal oxidation conditions of Iron.

Electronic arrangement of iron is [Ar] 3d6 4s2. Irons particular crystalline structure and electronic arrangement make normally alluring to metals. It is named as ferromagnetic materials. Iron displays diverse sorts of allotropic structures despite the fact that they don’t contain a solitary crystalline structure. There are allotropic types of iron and are named as alpha, delta and gamma iron.

Iron displays these three allotropic structures at various temperatures when it chills off to liquid structure. The electronic setup of Fe2+ is 1s2 2s2 2p6 3s2 3p6 3d6 and Fe3+ is 1s2 2s2 2p6 3s2 3p6 3d5. Fe2+ contains 2 lesser electrons contrasted with electronic design of Fe.

Applications of Iron

• Nitrates and iron chloride are utilized as modern reagents. The iron sulphate is utilized in the fungicide.
• They are usually utilized in the assembling of structures of substantial boats, autos, different machine devices and machine parts.
• Iron Chloride utilized in treating sewage frameworks.
• Iron Sulphate is utilized to treat Iron Deficiency.
• Iron is these days utilized in different careful sorts of gear

History and properties of iron

Archaeologists gauge that individuals have been utilizing iron for over 5,000 years, as per Jefferson Lab. Truth be told, incidentally, probably the eldest iron known to people truly tumbled from the sky. In an investigation distributed in 2013 in the Journal of Archaeological Science, analysts analysed antiquated Egyptian iron dabs that date to around 3200 B.C. what’s more, found that they were produced using iron shooting stars. The Old Testament in the Bible additionally makes reference to press on numerous occasions.

Iron is generally acquired from minerals hematite and magnetite. In littler degrees, it can likewise be gotten from the mineral’s taconite, limonite and siderite, as indicated by Jefferson Lab. Iron has four diverse allotropic structures, which implies that it has four distinctive auxiliary structures in which particles bond in various examples. Those structures are called ferrites, known as alpha (which is attractive), beta, gamma and omega.

Iron is an imperative supplement in our eating regimen. Iron inadequacy, the most widely recognized wholesome insufficiency, can cause paleness and exhaustion that influences the capacity to perform physical work in grown-ups. It can likewise hinder memory and other mental capacity in youngsters, Ladies who have iron inadequacy while pregnant are at an expanded danger of having little and early children, the CDC cautions.

There are two sorts of dietary iron: heme iron and non-heme iron. Heme iron — which is the more promptly consumed kind of iron — is found in meat, fish and poultry, while non-heme iron — which is likewise ingested yet to a lesser degree than heme iron — is found in both plant nourishments, (for example, spinach, kale and broccoli) and meat. Individuals ingest up to 30 per cent of heme iron, contrasted with 2 with 10 per cent of non-heme iron, the ARC reports, including that nourishments wealthy in nutrient C, for example, tomatoes or citrus organic products can help ingest individuals assimilate non-heme iron.

Uses of Iron

1. Iron is a mystery – it rusts effectively, yet it is the most essential everything being equal.
2. Most is utilized to make steel, utilized in structural designing (fortified solid, braces and so forth) and in assembling.
3. There are a wide range of sorts of steel with various properties and employments. Normal carbon steel is a composite of iron with carbon (from 0.1% for gentle steel up to 2% for high carbon steels), with little measures of different components.
4. Combination steels are carbon steels with different added substances, for example, nickel, chromium, vanadium, tungsten and manganese. These are more grounded and harder than carbon steels and have a gigantic assortment of uses including spans, power arches, bike chains, cutting apparatuses and rifle barrels.
5. Hardened steel is impervious to consumption. It contains in any event 10.5% chromium. Different metals, for example, nickel, molybdenum, titanium and copper are added to improve its quality and functionality. It is utilized in design, heading, cutlery, careful instruments and adornments.
6. Cast iron contains 3– 5% carbon. It is utilized for funnels, valves and siphons. It isn’t as intense as steel however it is less expensive. Magnets can be made of iron and its amalgams and mixes.
7. Iron impetuses are utilized in the Haber procedure for creating smelling salts, and in the Fischer– Tropsch process for changing over syngas (hydrogen and carbon monoxide) into fluid energizes.
8. Iron is a basic component for all types of life and is non-dangerous. The normal human contains around 4 grams of iron. A great deal of this is in haemoglobin, in the blood. Haemoglobin conveys oxygen from our lungs to the cells, where it is required for tissue breath.
9. People need 10– 18 milligrams of iron every day. An absence of iron will make sickliness create. Sustenance, for example, liver, kidney, molasses, brewer’s yeast, cocoa and liquorice contain a great deal of iron.
10. Iron is the fourth most plentiful component, by mass, in the Earth’s covering. The centre of the Earth is believed to be to a great extent made out of iron with nickel and sulphur.
11. The most well-known iron-containing metal is haematite, yet iron is found generally appropriated in different minerals, for example, magnetite and taconite.
12. Financially, iron is delivered in a shoot heater by warming haematite or magnetite with coke (carbon) and limestone (calcium carbonate). This structures pig iron, which contains about 3% carbon and different debasements, however, is utilized to make steel. Around 1.3 billion tons of unrefined steel are created worldwide every year.

Glycogen – Structure and Functions of Glycogen

Glycogen, a polysaccharide is the primary storage form of glucose in the human and animal cells for future use. It is present in the form of granules in the cytosol in many cell types. It is a multi-branched polysaccharide of glucose that remains as a form of energy storage in humans, fungi, animals, and bacteria. It is stored in the liver, muscle, and skeletal cells.

Structure of Glycogen:

Glycogen can be organized in a spherical form in which the glucose chains are structured around a core protein of glycogen with 38,000 molecular weight and it looks like branches of tree originated from a center point.

A branched polymer of glucose is called glycogen. The glucose residues are associated linearly by α-1, 4 glycosidic bonds and nearly 8- 10 residues a chain of glucose branches off through α-1, 6 glycosidic linkages. Helical polymer structure is formed by the α- glycosidic bonds.

Granules in the cytoplasm are formed by hydrating glycogen with 3-4 parts of water which will be 10-40 nm in diameter. At the core of glycogen, the granule is located the protein glycogen in which is involved in glycogen synthesis. It is an analog of starch which is the important form of storage of the glucose in most plants also starch has few branches and it will be in less compact when compared to the glycogen.

Functions of Glycogen:

In human beings and animals, glycogen is found mainly in the liver and muscle cells. It is synthesized from glucose when the sugar level in the blood is high and it serves as a ready source of glucose for the tissues throughout the entire body when sugar level in the blood reduces.

Muscle Cells:

Glycogen accounts for only 1-2% of the muscles by weight. Though, given the greater mass of muscle in the body, the total amount of glycogen storage in the muscles will be greater than that of the storage in the liver. The glycogen present in the muscles is provided only to the muscle cell itself. The enzyme glucose-6-phosphate will not be expressed by the muscle cells that will be required to release the glucose into the bloodstream.

The energy is provided to the muscles during any exercise or stress is experienced by the body. It is done by the breakdown in the muscle fibers of the glucose-1 phosphate produced from glycogen and converting into glucose-6 phosphate.

Liver Cells:

In the liver cells, the glycogen makes up to 6-10% of the liver by weight. If the food taken is not digested, then the blood glucose level increases and the insulin are released from the pancreas promoting the uptake of glucose into the liver cells. The enzymes involved in the glycogen synthesis are activated by the insulin.

When the insulin and the glucose levels are high, the glycogen chains by the addition of glucose molecules are extended and this process is called glycogenesis. The glycogen synthesis ceases as the glucose level and the insulin level decreases. If there is a decrease in the blood sugar level below a certain level, the glucagon released from the pancreas gesture the liver cells to break down glycogen. The glycogenesis process occurs and the glucose is released into the bloodstream.

Hence the glycogen will serve as the main shield of blood glucose level by storing the glucose during high sugar level in the blood and releasing it when the sugar level is low. Simply glycogen breakdown for supplying glucose will not be sufficient to meet the energy needs of the body so, in addition to this glucagon, cortisol, epinephrine and norepinephrine will also stimulate the breakdown of glycogen.

Other Tissues:

Glycogen can also be found in smaller amounts in other tissues like kidney, white blood cells, and red blood cells and in addition to the muscle and liver cells. In order to provide the energy needs of the embryo, the glycogen will be used to store the glucose in the uterus. The glycogen after the breakdown will enter the glycolytic or pentose phosphate pathway or it will be released into the bloodstream.

Bacteria and Fungi:

Microorganisms like bacteria and fungi possess some mechanisms for storing the energy to deal with the limited environmental resources; here the glycogen represents the main source for the storage of energy. The nutrient limitations such as low levels of phosphorus, carbon, sulfur or nitrogen can stimulate the glycogen formation in yeast. The bacteria synthesize glycogen in response to the readily available carbon energy sources with restriction of other required nutrients. The yeast sporulation and bacterial growth are associated with glycogen accumulation.

Metabolism of Glycogen:

The glycogen haemostasis which is a highly regulated process will allow the body to release or store the glucose depending upon its energetic needs. The steps involved in glycogen metabolism are glycogenesis or glycogen synthesis and glycogenolysis or glycogen breakdown.

Glycogenesis or Glycogen Synthesis:

The glycogenesis requires energy that is supplied by Uridine Tri-Phosphate (UTP). glucokinase or hexokinase first phosphorylate the free glucose to form glucose-6 phosphate which will be then converted to glucose-1 phosphate by the phosphoglucomutase. The UTP glucose-1 phosphate catalyzes the activation of glucose in which the glucose-1 phosphate and UTP react to form UDP glucose.

The protein, glycogen catalyzes the attachment of UDP glucose, itself in the glycogen synthesis. Glycogenin contains a tyrosine residue in each subunit that will serve as an attachment point for the glucose further glucose molecules will be then added to the reducing end of the previous glucose molecule in order to form a chain of nearly eight glucose molecules. By adding glucose through α-1, 4 glycosidic linkages the glycogen synthase then extends.

The branching catalyzed by amyloid 1- 4 to 1- 6 transglucosidases is called as the glycogen branching enzyme. A fragment of 6- 7 glucose molecules gets transferred from the glycogen branching enzyme from the end of a chain to the C6 of a glucose molecule that is situated further inside of the glucose molecule and forms α-1, 6 glycosidic linkages.

Glycogenolysis or Glycogen Breakdown:

The glucose will be detached from glycogen through the glycogen phosphorylase which will eliminate one molecule of glucose from the non-reducing end by yielding glucose-1 phosphate. The glycogen breakdown that generates glucose- 1 phosphate is converted to glucose- 6 phosphates and this is the process that requires the enzyme phosphoglucomutase.

Phosphoglucomutase will transfer a phosphate group from a phosphorylated serine residue within the active site to C6 of glucose- 1 phosphate and it will be attached to the serine within the phosphoglucomutase and then the glucose- 6 phosphates will be released.

Glycogen phosphorylase will not be able to cut glucose from branch points, so the debranching will require 1- 6 glucosidase, glycogen debranching enzyme (GDE) or 4- αglucanotransferase which will have glucosidase activities and glucosyltransferase. Nearly four residues from a branch point, the glycogen phosphorylase will be unable to remove the glucose residues.

The GDE will cut the final three residues of the branch and it will attach them to C4 of a glucose molecule at the end of another branch and then eliminate the final α- 1- 6 linked glucose deposit from the branch point.

Glycogen and Diet:

The food is taken, and the activities done can influence the production of glycogen and the way the body will function. With a low- carb diet, the primary source for glucose synthesis i.e. the carbohydrate will be suddenly restricted.

During the start of a low- carb diet, the glycogen stores will be severely depleted which will result in symptoms of mental dullness and fatigue. Then when the body starts to adjust and renew its glycogen stored then the body will return to the normal stage. Any weight loss effort can trigger this effect to some extent.

At the starting of a low- carb diet, the body will experience a huge drop in weight which will plateau and may even increase after a period of time. This is mainly because of the glycogen which will be composed mainly of water that will be 3- 4 times the weight of glucose itself.

The rapid depletion of glycogen at the beginning of the diet will trigger the rapid loss of water weight. Then, when the glycogen stores are renewed, the water weight returns causing weight loss to halt. It is necessary to keep in mind that this is caused by the temporary gain in water weight and not the fat and the fat loss can continue in spite of this short-term plateau effect.

During exercise, the body undergoes glycogen depletion and most of the glycogen will be depleted from the muscle. So while doing exercise, the persons can use carbohydrate loading which means the consumption of large amounts of carbohydrates in order to increase the capacity for the storage of glycogen. Glycogen is different from the hormone glucagon and it also plays an important role in carbohydrate metabolism and blood glucose control.

How Glycogen is used:

At any time, there will be nearly 4 grams of glucose in the blood. When the level declines, either because of missing any meals or during exercise when the glucose is burnt the insulin level will drop. During this, an enzyme called glycogen phosphorylase will break the glycogen separately in order to supply glucose to the body when it needs.

For the next 8- 12 hours, the glucose derived from the liver glycogen will be the main source of energy for the body. Out of all the body organs, the brain will use more than half of the blood glucose during inactivity and nearly 20% of it during an average day.

Metals and Nonmetals – Types, Properties and Differences

Introduction:

Every object around us can be categorized into two types of elements: metals or non-metals. Your books, clothes, pencil, water bottle, bag, table, the door are all examples of non-metals. Therefore, it is important to know the properties of Metals and Non-Metals and how to distinguish between them.

The periodic table:

The periodic table comprises an arrangement of elements based on certain chemical properties that they exhibit. The metals are arranged on the left side and the non-metals on the right side of the periodic table. The rows of the table are called periods and columns are called groups. There is a total of 92 elements that are known to be found naturally, out of which 70 are metals and 22 are non-metals.

Metals:

In the above depiction of the periodic table, most of the elements are metals. There are various kinds of metals:

• alkaline earth metals,
• alkali metals,
• transition metals,
• actinides, and
• lanthanides

Metals which are placed on the left-hand side of the periodic table are separated from non-metals by a zigzag line that starts from Carbon (C) and runs down Phosphorus (P), Selenium (Se), Iodine (I), till Radon (Rn). Therefore, these chemical elements and everything on their right is non-metal and the row just to their left is known as semi-metals or metalloids. They have properties that are common to both metals and non-metals.

Physical Properties:

• Metals occur in the solid state. All metals are solid except with an exception for mercury which is in liquid state in its natural form.
• Metals are malleable in nature. They can be beaten into thin sheets. For example, elements such as aluminium, gold, and silver can be beaten into thin sheets for common usage purpose.
• Metals are ductile. This means that metals can be stretched into thin wires. We can make copper wires and aluminium wires. All metals are equally ductile. Only that some metals are more ductile than others for which they are used for day to day purposes.
• Metals conduct heat and electricity. It is by virtue of this property of metals that heat, and electricity can pass through them. Every metal is a good conductor of heat and electricity.

Note: Silver is the best conductor of heat and electricity, copper is also a good conductor. The worst conductor of heat is lead whereas Iron and mercury are poor conductors of electricity.

• Metals are shiny. It is due to this property of metals that they are lustrous, and they reflect the light incident on its surface. Also, metals can be polished, and this is one of the reasons why metals are used to make jewellery and desired by women and men alike.
• Metals are very strong and hard, exceptions being sodium and potassium. They can be cut with a knife.
• Metals are also known to be heavy.
• Metals are also sonorous. They produce a sound when they are rung or hit with any object.
• Metals have a high melting point and a high boiling point.
• Metals have high density.
• Metals in the form of objects are opaque and are never transparent or translucent.

Chemical Properties:

• Metals easily corrode very easily and fast.
• Metals lose electrons easily. Their outer shell has 1, 2 or 3 electrons.
• Most metals form metal oxides when they come in contact with the oxygen.
• Metals have low electro-negativities, they are electropositive elements.
• Metals are also good reducing agents.

Non-Metals:

The non-metal elements are those that do not possess the properties of metals. The number of non-metals on the periodic table is very less as compared to metals. Non-metals are positioned on the right side of the periodic table. Some examples of the non-metals are hydrogen, carbon, nitrogen, phosphorus, oxygen, sulphur, selenium, all the halogens, and the noble gases.

Physical Properties:

• Non-metals are brittle and break into pieces when beaten. Example: Sulphur and phosphorus.
• Non-metals are not ductile so, they cannot be made into thin wires.
• Non-metals are insulators or poor conductors of electricity and heat because they do not lose electrons to transmit the energy.
• At room temperature, they can be in the state of solids, liquids or gases.
• They are non-sonorous.
• They can be transparent.

Chemical Properties:

• Non-metals generally have somewhere around 4 to 8 electrons in the outer shell.
• Non-metals tend to gain or accept valence electrons.
• When they are exposed to oxygen, non-metals react with oxygen to form acidic oxides.
• Non-metals have high electro-negativity; they are electro-negative elements.
• Non-metal elements are good oxidizing agents.
• These elements do not react with water.

Comparison of physical properties of metals and non-metals:

Property type	Metals	Non-metals
Physical State	Solid at room temperature. Exception being mercury and gallium.	Exist as solids and gases, exception being bromine.
Density	Highly dense	Low.
Melting and boiling points	High melting point and boiling point Exception being gallium and caesium.	Low melting point and boiling point. Exception being diamond and graphite.
Malleability and Ductility	malleable and ductile	not malleable or ductile.
Conductivity	Conducts heat and electricity	Poor/ bad conductors of heat and electricity exception being graphite.
Lustre	Shining lustre	They have no lustre except for iodine.
Sonorous sound	Sonorous.	Non-sonorous.
Hardness	Generally hard exception being Na, K	Generally soft except diamond

Comparison of chemical properties of metals and non-metals:

Reaction type	Metals	Non-metals
Reaction with H2O	Metals on reacting with water form metal oxides or metal hydroxides and release H2 gas.	Non-metals cannot give electrons to hydrogen in water to be released as H2gas. Non-metals have no reaction with water.
Reaction with O2	Metals react with oxygen to form basic oxides.Zn and Al form amphoteric oxides which show the properties of both acidic and basic oxides.Mostly, metal oxides are insoluble in water. Some of them dissolve to form alkali.	Non-metals react with oxygen to form oxides.Non- metal oxides are soluble in water. They dissolve in water to form acids.
Reaction with acids	Metals react with acid to form salt and release hydrogen.When metals react with HNO3, H2 is not released. HNO3 is strong oxidizing agent.	No reaction with acids occurs to release H2 gas. Non-metals don’t lose electrons to give it to hydrogen ions of acids.
Reaction with salt solutions	When metals react with salt solution, more reactive metals displace less reactive metals from its salt solution.	Here, more reactive non-metals displace less reactive non-metals from its salt solution.
Reaction with chlorine	Metals react with chlorine to form metal chloride. It is an ionic bond.What we get is an ionic compound	Non-metals react with chlorine to form non-metal chloride. It forms a covalent bond. What we get is a co-valent compound.
Reaction with H2	Only highly reactive metals react with hydrogen to form metal hydride.	Non-metals react with hydrogen to give hydrides.

Table of reactivity series shows order in which the metals are arranged based on their comparative reactivity.

Steps involved in the extraction of metals from the ore:

Calcination and Roasting:

Calcination	Roasting
In this process, ores are heated in the absence of oxygen where metal oxide is formed and CO2 releases.It is done for carbonate ores CaCO3 → CaO + CO2(g)	In this process, sulphur ore is heated in the presence of oxygen. Metal oxide is formed and SO2 gas releases.It is done for sulphide ores. ZnS+ 3O2 heat 3ZnO+ SO2

Questions

1. Take samples of Fe, Cu, Al, Mg and note the appearance of each sample.

2. Give an example of each:

i. Metal which is liquid at room temperature.

ii. Metal which can be easily cut with knife.

iii. A metal which is a good conductor of heat.

3. Explain the meaning of malleable and ductile.

4. What do you mean by displacement reaction?

5. Give one example of displacement reaction.

6. If you have ever seen a blacksmith beating an iron piece? What change did you find in the shape of these pieces on beating? Would you find a similar kind of change in wood log on beating?

7. Name two most malleable metals.

8. Prove the fact that metals are good conductors of electricity activity comes into equation.

9. List some physical properties of the metals.

10. Write some physical properties of non-metals.

11. What happens when sodium and water.

12. Why non – metals do not react with water?

13. Fill in the blanks:

i. Non- metal oxides are ……………… in water.

ii. Non-metals don’t lose electrons to give it to hydrogen ions of ……….

iii. In this calcination, ores are heated in the absence of oxygen where metal oxide is formed and ………………… releases.

iv. In roasting, In this perocess, metal oxide is obtained and ……………….. gas releases.

v. When metals react with salt solution, more reactive metals …………………. less reactive metals from its salt solution.

vi. Non-metals are …………… and break into pieces when beaten.

vii. Non-metals are not …………… so, they cannot be made into thin wires.

14. Give three reasons for the following:

(i) Why sulphur is a non-metal?

(ii) Why magnesium is a metal?

(iii) You are given three different samples of metals. Sodium, magnesium and copper. Write any two activities to arrange them in order of decreasing activity.

Polarity Chemistry – Polar and Non-Polar Molecules
Definition of Polarity

“A state or a condition of a molecule having positive and also negative charges, particularly in case of magnetic or electrical poles.

All molecules have a permanent number of electrons which are arranged at certain energy levels called a shell. The electrons present in valance shell are involved in chemical bonding with other atoms. Atoms tend to get the nobel gas configuration to attain stability. So, we can conclude that chemical bonding is responsible for stability of atoms and form molecules. On the basis of participation of atoms and shifting of electrons, chemical bonds can be of different kinds like a metallic bond, covalent bond, ionic bonds etc. Ionic bonds have the electrostatic force of attraction between two oppositely charged ions. These ions are formed after shifting of electrons. When an atom receives an electron, it gets a negative charge and becomes an anion. In the same way, when an atom gives away an electron, it gets a positive charge and becomes a cation.

A cation and anion attract each other due to opposite charges and this electrostatic attraction force is known as an ionic bond. In the course of the formation of the ionic bond, electrons completely transfer to atoms, therefore, there are negative and positive charges on ions. Such types of bonds are established between metals and non-metals. Metals tend to release electron and form cation. On the other hand, non-metals tend to receive electrons and form anion. Unlike ionic bonds, covalent bonds are made by equal sharing of valence electrons of bonding atoms. In such type of bonds, the bonding atoms share an equal number of valence electrons with each other. These shared electrons are placed exactly at the core of chemical bonds, therefore, there is no charge on any of the bonding molecule.

Covalent bonds are typically found between two non-metals or elements with similar electronegativity. For instance, the chlorine molecule is formed by equal sharing of electrons (one electron from each chlorine atom) from bonding atoms. Every covalent bond is made by sharing of two electrons. If an atom needs more than one electron to get Stable configuration, it can share the same number of electrons to form covalent bonds.

It results in the development of multiple covalent bonds like two oxygen atoms are bonded with double covalent bonds by the distribution of two electrons from each oxygen atom. In the same way, two nitrogen atoms are bonded with a triple covalent bond to get a steady nitrogen molecule.

What is Polarity in Chemistry?

We know there are many physical properties of compounds like density, melting and boiling points, solubility, volume etc. One of the significant properties of molecules is polarity. The polarity of molecules disturbs other physical properties of the molecules. The polarity of a molecule depends on the type of chemical bonding in the molecule and also on the bonded atoms.
If there is a clear separation of charges, we assume that there is polarity in the molecule. Polarity can be with an ionic and covalent bond. Several of the molecules have polar chemical bonds but still non-polar in nature due to the equal arrangement of the chemical bonds. Polarity, in common, refers to the physical properties of compounds such as boiling point, melting points, and their solubility. The polarity of bonds mainly arises from the space between molecules and atoms with difference in electronegativities. Moving on, usually, the term Polarity is used in areas like magnetism, electricity, and signaling of electronic devices. Consider an electromotive force (EMF) or an electric potential, acting between two poles.. The pole having more electrons has a negative polarity whereas the other end has a positive polarity.

Discussing polarity in Chemistry, well it is mostly the separation of an electric charge which leads a molecule to have a positive and negative end. Consider the below illustration-

In an H-F bond, the fluorine atom is more electronegative than that of the Hydrogen atom. The electrons spend more time at the Fluorine atom. Therefore, this F atom marginally becomes negative whereas the Hydrogen atom tends to become slightly positive.

Polarity of Molecules

The bond or the molecular polarities relies upon the electronegativity of the atoms or the molecules. A molecule is mostly said to be either a polar molecule, non- polar molecule or ionic molecule.

• Polar Molecules: A polar molecule is typically formed when the one end of the molecule is said to have the high number of positive charges and whereas the opposite end of the molecule has negative charges, generating an electrical dipole.
• When a molecule or atom is said to have a polar bond, then the center of the negative charge will be on one side, whereas the center of positive charge will be on the other side. The complete molecule will be a polar molecule.
• Non- Polar Molecules: A molecule or atom which does not have any charges present at the end due to the reason that electrons are equally distributed and those which symmetrically cancel out each other are the non- polar molecules.
• In a solution, a polar molecule cannot be mixed with the non-polar molecule. For example, take water and oil. In this, water is a polar molecule whereas oil act as a non-polar molecule. These two molecules do not form a solution as they cannot be mixed up together.

Polar and nonpolar molecules examples.

A molecule or atom may be polar or non-polar. A non-polar molecule has a configuration of its atoms lined up in a way that the orbital electrons are in the outer region canceling out the electronegativity.

• In common, pyramid-shaped and V-shaped molecules are called polar. Whereas the Linear molecules are said to be non-polar.
• Water is said to be a polar molecule due to the dissimilarity in the electronegativity between the oxygen atom and the hydrogen. Oxygen is an extremely electronegative atom when compared to hydrogen.
• Fats, petrol, oil, gasoline are known to be non-polar molecules as they do not dissolve in water and nonpolar are insoluble in water.
• Glucose is one more example of a polar molecule based on the configuration of the oxygen and hydrogen atoms in it.

Bond Polarity Example

Bond polarity signifies a separation of charge in a molecule. It can be calculated by the dipole moment of the chemical bond. If a chemical bond is formed between atoms with different electronegativities, the bonding electrons somewhat get shifted towards a more electronegative element. It induces slightly negative and positive charges over atoms. The polarity in bond gives the polarity to the molecule. For example; hydrogen chloride is a polar molecule because there is only one chemical bond that is polar in nature due to slightly negative and positive charges on bonding atoms.

The polarity in the bond is characterized by an arrow pointing towards the more electronegative atom

The total of polarity of all chemical bonds in a molecule gives the polarity of that molecule.

Factors on which the Polarity of Bonds Depends:

1) Relative Electronegativity of Participating Atoms or molecules.

Since the bond polarity involves dragging of electrons towards itself, so a more electronegative element will be able to attract the electrons more towards itself. As a result, the electrons will absolutely move towards the more electronegative element. The amount of their transfer will depend upon the relative electronegativity of the participating atoms.

2) The Spatial Arrangement of Various Bonds in the Atom or molecule.

The shared pair of electrons also experience dragging force from the other bonded and non-bonded pair of electrons. This results in different bond polarity among the same participating atoms that are present in other molecules. For e.g. Bond Polarity of O-H bond in an H2O molecule and acetic acid molecule is much different. This is due to the different spatial arrangement of many bonds in the molecule.

What are Factors Determine Whether or Not a Molecule Is Polar?

1. If the molecule or atom is perfectly symmetric, the molecule will not be polar even if there are polar bonds present.
2. Polar bonds are formed when one atom in the bond has a much tougher pull towards electrons than the other atom. The difference in strength can be expected by comparing electronegativity values. If one electronegativity value is greater, that atom will pull the electron closer and develop a partial negative charge, while the other atom develops a partial positive charge.

Solved Example for You

Problem 1: C, H, O, N and S have the electronegativity 2.5, 2.1, 3.5, 3.0 and 2.5 . Among the following bond which is most polar?
A) O – H B) S – H C) N – H D) C – H

Solution: A) The difference in the electronegativity between two or more atoms is more; the bond among them is more polar. For the given atoms, we can see that:

• O – H = 3.5 – 2.1 = 1.4
• S – H = 3.5 – 2.5 = 1
• N – H = 3.0 – 2.1 = 0.9
• C – H = 2.5 – 2.1 = 0.4.

Hence, the O-H bond is the most polar among the given bonds.