Molecule The smallest particle of substance (element or compound) which can exist free in nature independently. Molecule may contain one, two or more than two atoms.e.g. He,Ne,H2, H2O,NH3,CH4 The number of atoms contain a molecule is called atomicity. Molecules formed from one atom are called mono atomic molecule e.g. molecule of He, Ne.Molecules containing two atoms are called diatomic molecules e.g. H2, N2, CO, HCl and containing more than two atoms are called polyatomic molecules. Molecules may be formed from similar atoms like H2, N2, O2 and O3, S8 and may from different atoms like H2O, NH3. Some molecules are so big, that their M.wt are generally in thousands are called Macro molecules e.g. molecules of hemoglobin, starch cellulose etc. Haemoglobin molecule is approximately 68000 time heavier than hydrogen atom. Molecules of the same substance are similar in properties. These molecules have empty space in them which is maximum in gas and minimum in solid. Molecular mass is the sum of the atomic mass of all the atoms in molecule. Molecular mass is represented by a.m.u. Molecules having two similar atoms is called homo nuclear molecule. e.g.H2, F2, O3 , S8 These are the molecules of the elements. Molecule having two different elements is called hetro nuclear molecule. e.g. H2O , H2SO4 , CO2 . These are the molecules of the compounds.
Posted on: Fri, 11 Apr 2014 13:26:11 +0000
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