Elements of group 13 mainly form covalent compounds because ______

(a)

small size

(b)

electro negativity values are high

(c)

ionization energy is very high

(d)

both (a) and (c)

All elements except carbon have the tendency to show maximum covalency of six ______

(a)

due to presence of vacant d-orbitals

(b)

due to absence of vacant d-orbitals

(c)

due to presence of partially filled d-orbitals

(d)

due to presence of completely filled d-orbitals

Group 14 elements have general electronic configuration _______.

(a)

ns²

(b)

ns²np⁴

(c)

ns²np⁶

(d)

ns²np²

The silicates which contain discrete tetrahedral units are _______.

(a)

ortho silicates

(b)

sheet silicates

(c)

pyrosilicates

(d)

three dimensional silicates

Borax is _______.

(a)

Na₂[B₄O₅(OH)₄).8H₂O

(b)

Na₂[B₄O₅(OH)₆).7H₂O

(c)

Na₂[B₄O₃(OH)₈].6H₂O

(d)

Na₂[B₄O₂(OH)₁₀).5H₂O