Stoichiometry and calculations based on stoichiometry Stoichiometry is the calculation of the quantities of reactants and products involved in a chemical reaction. The word ‘Stoichiometry’ is derived from two Greek words – stoicheion (meaning element)
Percentage Composition Percentage composition of a compound is the relative mass of each of the constituent elements in 100 parts of it by mass. The percent composition of a compound is expressed by identifying the
Dalton’s Atomic Theory Dalton put forward his theory in 1803. He proposed that compounds were formed by the combination of atoms of different elements in small, whole number ratios, but had no certain method for
Atomic mass Every particle of matter has some amount of mass associated with it whether small or large. Everything is made up of atoms. Mass of an atomic particle is called the atomic mass. This
Valence Shell Electron Pair Repulsion Theory The basic concept of this theory as suggested by Sidgwick and Powell (1940) has provided a highly useful idea for predicting geometries of molecules. According to this model, the
Fajan’s rule: Polarisation (Change of Ionic Character to Covalent Character) When two oppositely charged ions of unequal size approach each other closely (during formation of an electrovalent bond), the ion smaller in size attracts outermost
Valence Bond Theory (VBT) This theory was presented by Heitler and London to explain the formation of covalent bond. The main postulates of this theory are: (i) A covalent bond is formed by the overlapping
Properties of Covalent Bonds: Bond Length: Internuclear distance between two atoms in a molecule is called bond length. Bond length in covalent compound (AB) = rA + rB The following factors affect the bond length
Covalent Bond A covalent bond may be defined as the bond formed by mutual sharing of electrons between the combining atoms. Examples: 1. Formation of chlorine molecule Chlorine atom has seven electrons in the valency
Electrovalent or Ionic Bond (a) Chemical bond formed between ions is called ionic bond. (b) Ionic bonds are formed by loss and gain of e– between two atoms. (c) The electrostatic force of attraction developed
