MCQ
Radius of the isoelectronic species
- AIncreases with the increase of nuclear charge
- ✓Decreases with the increase of nuclear charge
- CIs the same for all
- DFirst increases and then decreases
✓
Answer
Correct option: B.
Decreases with the increase of nuclear charge
b
An isoelectronic series is a group of ions that all have the same number of electrons. For example, one isoelectronic series could include $O ^{2-}, F ^{-}, Na ^{+}, Mg ^{2+}$. These all have ten electrons.The number of protons, though, increases as atomic number increases, so nuclear charge increases. When we consider effective nuclear charge then, the ions of greater nuclear charge attract those ten electrons more strongly and pull them in more tightly. Therefore, the radii of the ions in an isoelectronic series decrease as nuclear charge (or atomic number) increases.
An isoelectronic series is a group of ions that all have the same number of electrons. For example, one isoelectronic series could include $O ^{2-}, F ^{-}, Na ^{+}, Mg ^{2+}$. These all have ten electrons.The number of protons, though, increases as atomic number increases, so nuclear charge increases. When we consider effective nuclear charge then, the ions of greater nuclear charge attract those ten electrons more strongly and pull them in more tightly. Therefore, the radii of the ions in an isoelectronic series decrease as nuclear charge (or atomic number) increases.
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