CBSE Class 12th Chemistry Chapter1 The Solid State -Part2

Class XII Chemistry Chapter 1 The Solid State NCERT Solution is given below.

Question 1.3:
Classify each of the following solids as ionic, metallic, molecular, network (covalent) or amorphous.
(i) Tetra phosphorus decoxide (P4O10) (vii) Graphite
(ii) Ammonium phosphate (NH4)3PO4 (viii) Brass
(iii) SiC (ix) Rb
(iv) I2 (x) LiBr
(v) P4 (xi) Si
Answer
Ionic → (ii) Ammonium phosphate (NH4)3PO4, (x) LiBr
Metallic → (viii) Brass, (ix) Rb
Molecular → (i) Tetra phosphorus decoxide (P4O10), (iv) I2, (v) P4.
Covalent (network) → (iii) SiC, (vii) Graphite, (xi) Si
Amorphous → (vi) Plastic

Question 1.4:
(i) What is meant by the term ‘coordination number’?
(ii) What is the coordination number of atoms:
(a) in a cubic close-packed structure?
(b) in a body-centred cubic structure?
Answer
(i) The number of nearest neighbours of any constituent particle present in the crystal lattice is called its coordination number.
(ii) The coordination number of atoms
(a) in a cubic close-packed structure is 12, and
(b) in a body-centred cubic structure is 8