Question

what is atomicity of (NH4)2 SO4 and Al2O3

Answer 1

atomicity is a no. of atoms in a molecule.
(NH4)2 has 8 atoms of Hydrogen and 2 atoms of Nitrogen, the atomicity is 8+2=10.
same with SO4 and Al2O3,
atomicity(SO4) = 1 atom of S + 4 atoms of O = 5
atomicity(Al2O3) = 2 atoms of Al + 3 atoms of O
= 2+3 = 5

Answer 2

atomicity of (NH4)2 SO4 =

N = 2

H = 4 × 2 = 8

S = 1

O = 4

= 2 + 8+ 1+ 4 = 15

atomicity of Al2O3 =

Al = 2

O = 3

= 2+3 = 5