MCQ
Which among the following elements has the largest atomic radii?
- A$\ce{Na}.$
- B$\ce{Mg}.$
- ✓$\ce{K}.$
- D$\ce{Ca.}$
✓
Answer
Correct option: C.
$\ce{K}.$
$\ce{Na}$ and $\ce{K}$ belong to the same group.
i.e. Group $I. \ce{Ca}$ and $\ce{Mg}$ belong to the Group $\ce{II}$. The atomic radius decreases in moving from left to right along a period. This is due to an increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom. Hence $\ce{K}$ has largest atomic radii.
i.e. Group $I. \ce{Ca}$ and $\ce{Mg}$ belong to the Group $\ce{II}$. The atomic radius decreases in moving from left to right along a period. This is due to an increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom. Hence $\ce{K}$ has largest atomic radii.
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