MATTER Classification of matter Element Metals and non metals Symbols Molecules Chemical formula Compounds Mixture Formula unit, Formula mass and Molecular mass

CHAPTER NO.2 MATTER The physical material of the universe is called Matter. OR Anything having mass and occupies space is called Matter States of matter Ordinary matter can exist in three physical states Solids; Liquids and Gases. Examples Silver,Water and Oxygen.

Classification of Matter Mixture(Impure Substance) Compounds Elements Homogeneous Heterogeneous Metals Non-metals Molecular Compounds Ionic Compounds

PURE SUBSTANCES The substances which are made up of only one kinds of atoms, ions or molecules are called pure substances. Pure substances are further classified into Element Compound

Element Pure substance having all the atoms with same atomic number is called an element. Or A substance consisting of chemically identical atoms is called an element. Elements have distinct properties of their own and retain them under all conditions. Examples Gold is an element and if it is broken down into pieces, each piece will retain the properties of gold, similarly, Iron will remain Iron and Carbon will remain Carbon after division into smaller parts.

Classification of Elements Metals Non-Metals

Metals Those elements whose oxides and hydroxides are basic in nature and possess low I.E., E.N. and E.A. are called Metals

Properties of Metals They are sonorous, means that they give off a note when hit. They are malleable and can form sheets. They are ductile and can be drawn into wires. They are good conductors of heat and electricity. They have a relatively high densities. They have great tensile strength and can withstand stress and strain. They have high melting point and boiling point.

Non-metals Those elements whose oxides are acidic in nature and possess higher I.E., E.N., and E.A. are called non- metals. Sulphur Phosphorus

Properties of Non-metals They are non sonorous. They are neither malleable nor ductile. They are poor conductor of heat and electricity. They have relatively low densities. They are usually brittle and break easily when subjected to stress and strain. Non-metals have low melting point and boiling point.

SYMBOL An abbreviation used for the chemical name of an element is called symbol. OR Letter or letters which represent chemical name of an element is known as symbol.

Rules governing symbols of elements Symbols are composed of one, two or three letters. If one letter is used, it is capitalized. If two or three letters are used, the first is capitalized and the others are lowercase letters.

Some common elements whose symbols consist of first letter of their English names Boron Nitrogen Fluorine Sulphur Carbon Oxygen Phosphorus Iodine B N F S C O P I

Some common elements whose symbols consist of two letters of their names Helium Bromine Bismuth Calcium Beryllium Barium Chlorine Chromium He Br Bi Ca Be Ba Cl Cr

Some common elements whose symbols consist of first and second letters of their Latin names English Name Latin Name Symbol Potassium Iron Copper Silver Tin Antimony Tungsten Gold Mercury Lead Kalium Ferrum Cuprum Argentums Stannum Stibium Wolfram Aurum Hydrargyrum Plum bum K Fe Cu Ag Sn Sb W Au Hg Pb

Molecule The smallest particle of a substance which can exist independently as a separate unit and shows all the properties of that substance is called molecule. OR Atoms of most elements combine with either atoms of the same element or atoms of other elements to form molecules. Types of Molecules on bases of number of atoms: On the bases of number of atoms Molecules may be Mono atomic.(He,Ne and Ar). Diatomic. (H2,O2 and Cl). Triatomic. (H2O,CO2 and H2S). Polyatomic.(CH4,NH3 and C6H6).

Classification of Molecules Molecules of Elements Molecules of Compounds

Molecules of Elements The molecule which consists of a fixed number of one kind of atom chemically combined together is known as molecules of elements Oxygen Molecule Water Molecule Nitrogen Molecule

Molecules of Compounds The molecule consists of a fixed number of different kinds of atoms chemically combined together is known as molecule of compound. Carbon dioxide Molecule Sulphur dioxide Molecule Water Molecule

CHEMICAL FORMULA The symbolic representation of molecule of a compound is called chemical formula. OR The combination of symbols of elements present In a molecule of a substance is called chemical formula.

Examples of Chemical Formula Oxygen Hydrogen Ammonia Glucose Water O2 H2 NH3 C6H12O6 H2O

Method of writing a Chemical formula 1) Write the correct symbols of ions side by side. 2) Write the positive ions on left hand side and negative ions on right hand side. 3) Write the valency on the right top side of each ions. 4) Write the polyatomic radicals in brackets. 5)Cross the valencies to the lower right of each radicals. 6) if the valencies are equal then donot cross it.

Step 4. Mg+2 Cl-1 Step5. Formula =MgCl2 Examples Write the chemical formula for the molecules of the following compounds. 1.Magnesium Chloride Step 1. Magnesium chloride. Step 2. Mg Cl. Step 3. Mg+2 Cl-1 Step 4. Mg+2 Cl-1 Step5. Formula =MgCl2

Aluminium sulphate: Step 1. Aluminum sulphate. Step 2. Al SO4

Importance of Chemical Formula Chemical Formula help us to know about: Elements present in a molecule. 2.Number of atoms of each element present in a molecule. 3. Composition of the molecule.

Types of Chemical Formula Empirical Formula Molecular Formula Structural Formula

Empirical Formula The chemical formula which shows simplest ratio between the atoms present in a molecule of a compound is called Empirical Formula. Examples HO is the empirical formula of Hydrogen Peroxide. CH2O is the empirical formula of Glucose. CH is the empirical formula of Benzene. Note: All Ionic compounds are represented by their Empirical Formula.

Molecular Formula The formula which indicates the actual number of atoms in a molecule is called molecular formula. Molecular Formula represents molecular compounds. Example Molecular formula of Benzene is C6H6

Structural Formula Formula which indicates the arrangement of atoms and bonds in molecule is called structural formula. Angular Water Linear Carbon dioxide

Compound Compound is a pure substance which contains only one type of molecule made up of atoms of more one element. OR The pure substance formed by the chemical combination of two or more atoms of different element in a fixed mass ratio is known as compound. Example when Carbon is burnt in Oxygen, Carbon dioxide is formed.

Types of Compound Compound Ionic Compound Molecular Compound

Ionic Compound The type of Compound which is formed by the chemical combination of a large number of positive and negative ions is called Ionic compounds .Ionic compounds are generally crystalline, like NaCl.

Molecular Compound A compound that consists of separate, independent units or molecules, is called a molecular compound. Examples Water (H2O), Carbon dioxide(CO2),Benzene(C6H6) and Glucose (C6H12O6)

Mixture An impure substance formed by the physical combination of two or more pure or impure substances is called mixture. A mixture consists of two or more substance which are not chemically combined. The substances in a mixture could be all the elements, all compounds or a combination of elements and compounds. For Example:- Air is a mixture because it is composed of many gases like Nitrogen, Oxygen, Carbon dioxide and inert gases which are combined physically and are not in a fixed mass ratio.

Heterogeneous Mixture Types of Mixture Mixture Homogeneous Mixture Heterogeneous Mixture

Homogeneous Mixtures Mixtures having uniform composition throughout are called homogeneous mixtures. Examples Air, Steel, Salt, Sugar and water solution.

Hetrogeneous Mixture The mixtures which have different composition throughout its mass is called heterogeneous mixture. Examples Rocks, Soils and Ice-Cream etc….

Differences between Compounds and Mixtures 1. It is a pure substance. 2. It is formed by chemical combination. 3.Its composition Is fixed. 4.The combining substances lose their properties. 1. It is an impure substance. 2. It is formed by Physical combination. 3. Its composition is variable. 4. The combining substances doesn’t lose their properties. Compound Mixture

Differences between Compounds and Mixtures 5. It can’t be separated by any physical method. 6. Examples: Glucose, Water and Carbon dioxide gas etc….. 5. It can be separated by simple physical method. 6. Examples: Air, Rocks, Sugar solution etc…..

Formula Unit The smallest repeating unit of an ionic compound is called Formula unit. Example: NaCl indicates a formula unit, it can’t exist independently. In case of molecular compound, it may or may not exist independently. Example: H2O, NH3, CH4……. are the formula units exist independently. Here the formula unit and molecules of there compounds are the same. On the other hand, CH(from C6H6), CH2O(from C6H12O6), NaCl…… can’t exist independently. Therefore, they aren’t called molecules but they are called Empirical Formula. Formula unit is used for Ionic and Empirical formula is used for Covalent compounds.

Benzene molecule C C C C C H H H H H Emperical formula H Empirical Formula Emperical formula H Benzene molecule

[NaCl] is the FORMULA UNIT

Molecular mass The sum of atomic masses of all the atoms present in one molecule of a substance is called molecular mass. Examples Molecular mass of Benzene C6H6 = 6 × 12 + 6 = 78 Molecular mass of Glucose C6H12O6=6×12+12+6×16=180 Molecular mass of Carbon dioxide CO2 = 12+ 2×16 = 44 Molecular mass of Water H2O = 2 + 16 = 18 Note: The following points are important for finding molecular mass of a substance. 1) Correct chemical formula of the molecule. 2) Number of atoms of each element in a given molecule. 3) Atomic number of all atoms present in a molcule.

Formula mass It is the sum of atomic masses of all the atoms present in a formula unit or E.F Examples 1)Formula mass of Benzene( CH) = 12 + 1 =13 2)Formula mass of NaCl = 23 + 35.5 = 58.5