8 a
The atomic symbol is [tex]_{12}^{24}\text{Mg}^{2+}[/tex].
The 2+ superscript tells you that the atom has two + charges. It must add two – charges (electrons) to become a neutral atom.
The equation for the process is
[tex]_{12}^{24}\text{Mg}^{2+} + 2e^{-} \rightarrow _{12}^{24}\text{Mg}[/tex]
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8 b i
A neutral Mg atom has no charge because it has 12 protons (+)
and 12 electrons (-).
12(+)+ 12(-) = +12 – 12 = 0
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8 b ii
A magnesium atom loses two electrons when it forms an ion. The ion has
12 protons and 10 electrons.
12(+) + 10(-) = +12 – 10 = +2
