Answer:
a) 0
b) 4
c) 4
d) 4
e) 2
f) 4
Explanation: No. unpaired electrons:
a) square planar, strong field
d⁴ 0
b) tetrahedral, strong field
d⁴ 4
c) Octahedral, weak field
d⁴ 4
d) square planar, weak field
d⁴ 4
e) Octahedral, strong field
d⁴ 2
f) tetrahedral, weak field
d⁴ 4