Analysis shows that nickel oxide has the formula `Ni_(0.98)O_(1.00)`. What fractions of nickel "exist" as `Ni^(2+)` and `Ni^(3+)` ions?

Explanation

98Ni-atoms are associated with 100 O-atoms out of 98Ni-atoms, suppose Ni present as `Ni^(2+)=x`
Then Ni present as `Ni^(3+)=98-x`
total charge on `x Ni^(2+)` and `(98-x)Ni^(3+)` should
be equal to charge on 100 `O^(2-)` ions.
Hence `xxx2+(98-x)xx3=100xx2` or `2x +294-3x=200` or x=94
`therefore ` Fraction of Ni present as `Ni^(2+)={94}P98}xx100=96%`
Fraction of Ni present as `Ni^(3+)={4}{98}xx100=4%`