Ionic bonding in magnesium oxide
1 mark · EasyHow many electrons are in the outer shell of an oxide ion (O^{2-})?
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8 (±0)
Also accept: eight
Common mistakes: 6 (for a neutral O atom)
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Marking points
B1 · 1 mark · States 8 (electrons) as the number in the outer shell of O^{2-}.
Worked solution
An O^{2-} ion has 8 electrons in its outer shell.