
The formation of magnesium oxide is correctly shown in option :

- Mg with electron-dot structure combines with O (electron$\xrightarrow{\text{dot structure)}}$ Mg2+ [ :O: ]2- (single ion pair, dots transferred from Mg to O)
- Mg with one dot combines with O (electron$\xrightarrow{\text{dot structure)}}$ Mg+ [ :O: ]- (single electron transferred)
- Mg with electron-dot structure combines with two O atoms (electron$\xrightarrow{\text{dot structures)}}$ Mg2+ [ :O: ]-2 subscript 2 (two singly-charged oxide ions)
- 2Mg with a cross each combine with O: (electron$\xrightarrow{\text{dot structure)}}$ [Mg2+]2 [ :O: ]2- (two Mg2+ ions with one O2- ion)
Solution
Asked in: CBSE