MCQ
First ionization potential of $\ce{Mg}$ is less than that of :
- A$\ce{Li}$
- B$\ce{Na}$
- C$\ce{Ca}$
- ✓$\ce{Be}$
✓
Answer
Correct option: D.
$\ce{Be}$
First $\ce{I.E}$ of $\ce{Mg}$ is greater than that of $\ce{Na}\ ($because of the higher nuclear charge on $\ce{Mg})$ and also that of $\ce{Li.}$ Due to lts larger size, $\ce{Ca}$ has lower $\ce{I.P}$ than $\ce{Mg}. \ce{Be}$ has smaller size than $\ce{Mg}$. Hence $\ce{Be}$ has greater first $\ce{I.P}$ than $\ce{Mg}.$
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