nickel (II) oxide $2^+$
Work Step by Step
$NiO$ $Ni$ is nickel. $O$ is oxygen, which his called oxide when naming compounds. Oxygen has a charge of -2. The compound is neutral, so the charge/oxidation number of the nickel element was +2. The name is written as element(oxidation number) element so $NiO$ is nickel (II) oxide.