Question

Oxidation number of K4 [Ni (Cn)4]

Answer 1

Answer:

oxidation Of Ni=0( example of synergic bond effect

Answer 2

As Ni is the central metal atom here, so we will find it 's oxidation state ( as you had not mentioned in question of which element we need to find oxidation number).

1 × 4 + Ni + (-1) × 4 = 0

Ni = 0