VERSATILE NATURE OFCARBON • The compounds which are made up of carbon are known as ORGANIC COMPOUNDS and Organic chemistry is the term applied originally to the study of substances connected directly with animals and plants, so it is derived from the word “organism”. Today the study of organic chemistry is very important because it help us to understand the phenomena living in the world. Synthetic fibres, plastic, medicines, artificial sweeteners are product of industrial organic chemistry and the energy that man uses in every industrial activity derives mainly from the combustion of organic material found in coal an crude oil ORGANIC CHEMISTARY The symbol of carbon is C . The amount of carbon present in the earth’s crust & atmosphere is very small.the earth’s crust contains only 0. This is because carbon is the main constituent of coal.03% of Co2.• • Carbon is an element.). WHAT IS CARBON ??? .coal & petroleum etc. For example.and the atmosphere has only 0. The name carbon is derived from latin word ‘carbo’ which means ‘coal’.02% carbon in the form of minerals(like carbonates.It is a non-metal. plants & animals. The importance of carbon can be gauged from the fact that we are ourselves made of carbon compounds. IMPORTANCE OF CARBON…….all the living things. role in our daily life..carbon element has immense importance in every sphere of life. nylon & polysterwhich are used for making clothes are carbon compounds.are made up of carbon compounds(called organic compounds) A large no. .• • In spite of the small amount of carbon available in nature. silk . The materials like cotton. wool.pulsessugar.tea.fruits & vegetables.coffee.etc. It is clear that carbon plays a veryimp. In fact.Our food materials like grains. of things which we use in our daily life are made of carbon compounds. are carbon compounds.. • • We can test the presence of carbon in a material on the basis of the fact that carbon & its compounds burn in air to give Co2 gas which turns lime water milky. This test can be performed as follows: Burn the given material in air. . Pass the gas formed through lime water.. TO TEST THE PRESENCE OF CARBON IN A GIVEN MATERIAL.If the lime water turns milky. then the given material contains carbon. including the hydrogen.077 nm Carbon has four valence electrons and it must either gain four electrons or lose four electrons to reach a rare-gas configuration.55 Covalent radius 0.• Electronic configuration 1s2 2s2 2p2 Electronegativity 2. Carbon also forms strong double and triple bonds to nitrogen and oxygen. Carbon therefore forms covalent bonds with a large number of other elements. It can even form double bonds to elements such as phosphorus or sulfur that do not form double bonds to themselves. oxygen. Because they are relatively small. PHYSICAL PROPERTIES OF CARBON . and sulfur found in living systems. phosphorus. nitrogen. carbon atoms can come close enough together to form strong C=C double bonds or even C C triple bonds. COVALENT BONDING IS OF THREE TYPES: WHAT IS COVALENT BONDING?????? .Whenever a non-metal combines with another non-metal.It is formed when both the reacting atoms need to achieve inert gas configuaration.sharing of electrons takes place b/w their atoms & a covalent bond is formed.• • The chemical bond formed by sharing of electrons b/w two atoms is known as a covalent bond. • LOW MELTING & BOILING POINTS:-They are made up of electrically neutral molecules. Covalent compounds do not conduct electricity because they don’t contain ions.So.only some of them are solids.the force of attraction b/w the molecules of a compound is very weak. PROPERTIES OF COVALENT COMPOUNDS . Covalent compounds are insoluble in water but they are soluble in organic solvents. Covalent compounds are usually liquids or gases. • • If carbon could gain 4 electrons forming C4-anion.But it would be difficult for the nucleus with six protons to hold on to ten electrons. four extra electrons. Carbon overcomes this problem by sharing its valence electrons with other atoms of other elements.But it would require a large amount of energy to remove four electrons leaving behind a carbon with six protons in it’s nucleus holdind on to just two electrons. If carbon could lose 4 electrons forming C4+ cation.that is. WHY CARBON DOES NOT GAIN OR LOSE ELECTRONS???? . CATENATION:-Carbon has the unique ability to form bonds with other atoms of carbon. of compounds with oxygen.hydrogen & many other elements.giving rise to large no.nitrogen.The nature of covalent bond enables the carbon to form a large no.chlorine. VERSATILE NATURE OF CARBON .This property is called catenation. of compounds.• • CARBON IS TETRAVALENT:-Since carbon has a valency of four.sulphur.That is why carbon forms a large no.it is capable of bonding with four other atoms of carbon or atoms of other mono-valent element at a time. of compounds. OCCURRENCE OF CARBON .Another naturally occurring form of carbon called buckministerfullerene has been discovered recently.carbon occurs in nature in the form of compounds such as:i) Co2in air.Only a small amount of carbon occurs as free element in the earth’s crust. ii)carbonates(limestone. IN COMBINED STATE.Most of carbon occurs in the combined state. iii)Fossil fuels .iv)wood.marble & chalk).cotton & wool.fats & proteins. v) organic compounds like carbohydrates.carbon occurs in nature mainly in two forms:diamond & graphite.• • IN FREE STATE. • The various physical forms in which an element can exist are called allotropes of carbon.The three allotropes of carbon are : i)Diamond ii)Graphite iii)Buckministerfullerene ALLOTROPES OF CARBON . ii)It has hexagonal ii)It constitutes 20 Hedral structure rings. DIAMOND GRAPHITE BUCKMINISTER FULLERENE . density. iv)It has very high iv)It has very low iv) It has intermediate density . Density. to conduct electricity. electricity. hexaganol & 12 penta gonal rings. i)It is neither hard hard nor soft ii)It has a tetra.• • i)It is extremely i)It is very soft. iii)It doesn’t con.iii)It conducts iii) somewhat it is able ducts electricity. Tetrahedrel structure of Diamond USES OF DIAMOND . ii)Diamonds are used for making jewellery. iii)Sharp-edged diamonds are used by eye-surgeons as a tool to remove cataract from eyes with a great precision.• • i)It is used in cutting instruments like glass cutters & in rock drilling equipment. WHY GRAPHITE IS ABLE TO CONDUCT ELECTRICITY?? In graphite crystal.• • i)It is used as a lubricant for the fast moving parts of machinery.Thus fourth electron is free to move.it conducts electricity.each carbon atom is joined to 3 other carbon atoms by covalent bonds due to hexagonal rings. ii)It is used for making electrodes HEXAGONAL STRUCTURE in dry cells. OF GRAPHITE iii)It is used for making the cores of our pencils called ‘pencil leads’ & black paints.Due to presence of free electrons. USES OF GRAPHITE . Source of hydrocarbons is petroleum(or crude oil)which is obtained from underground oil deposits by drilling oil wells. TYPES OF HYDROCARBONS:-They are of two types:saturated hydrocarbons & unsaturated hydrocarbons HYDROCARBONS . The most imp.The natural gas which occurs above petroleum deposits also contains hydrocarbons.• • A compound made up of hydrogen & carbon only is called hydrocarbon(Hydrogen + carbon=hydrocarbon). The general formula of alkanes is CnH2n+2. SATURATED HYDROCARBONS .• • A hydrocarbon in which the carbon atoms are connected by only single bonds is called a saturated hydrocarbon. Alkanes are also said to be saturated hydrocarbons. Alkanes are chemically not reactive. of carbon atoms in one one molecule of the alkanes.They are quite unreactive.Where n is the no. • STRUCTURES & MOLECULAR FORMULAE OF FIRST FIVE ALKANES : • STRUCTURES & MOLECULAR FORMULAE OF FIRST FIVE ALKANES . These hydrocarbons are chemically very reactive. Alkenes or alkynes are also called unsaturated hydrocarbons . These are of two types:-Alkenes & Alkynes UNSATURATED HYDROCARBONS .• • A hydrocarbon in which the two carbon atoms are connected by a double bond or a triple bond is called an unsaturated hydrocarbon. They are obtained mostly from petroleum by a process called cracking. of carbon atoms in its one molecule.The simplest alkene is ethene . The general formula of an alkene is CnH2n where n is the no.• An unsaturated hydrocarbon in which the two carbon atoms are connected by a double bond is called an alkene. ALKENES . The names & molecular formula of the first 3 alkenes are given below. The simplest alkyne is ETHYNE. of carbon atoms in one molecule of the alkyne. The general formula of an alkyne is CnH2n-2 where n is the no.H H C C ALKYNES . The names & molecular formulae of the first 3 alkynes are given below.• • An unsaturated hydrocarbon in which the two carbon atoms are connected by a triple bond is called an alkyne. ETHYNE:. Organic Chemistry:Functional Groups : • Organic Chemistry:Functional Groups .The Formula of benzene is C6H6 & the Structure of benzene is shown Alongside.• • CYCLIC HYDROCARBONS These alternating single and double bond hydrocarbons form a ring. Many of these compounds have strong aromas or odors. An unsaturated cyclic hydrocarbon is ‘benzene’. Some of the imp. we will focus on some of them Useful to group the infinite number of possible organic compound.Functional groups : Functional groups Functional groups are parts of molecules that result in characteristic features About 100 functional groups exist. Functional groups present in organic compounds are : i)Halo group ii)Alcohol group iii)Aldehyde group iv)Ketone group v)Carboxylic group . The first four members of haloalkanes are given in the table.bromine &iodine are collectively known as halogens & are represented by the general symbol –X.The haloalkanes can be written as R-X(Where R is an alkyl group & X is the halogen atom).We can also write the corresponding bromoalkanes or iodoalkanes. CHLOROMETHANE H H C Cl H HALO GROUP . The elements chlorine. The alcohol group consists of one oxygen atom & one hydrogen atom joined together. The general formula is R-OH(where R is an alkyl group & OH is the alcohol group).ETHANOL H H H C C OH H H ALCOHOL GROUP: -OH . This group is also known as hydroxyl group. The aldehyde group consists of 1 carbon.1 hydrogen atom joined together.1 oxygen. This group is attached either to a hydrogen atom or an alkyl group. The aldehydes can be represented by general formula RCHO(where R is an alkyl group). ETHANAL H O H C C H H ALDEHYDE GROUP: -CHO OR H C O .