When an atom loses an electron to form a cation, the size typically:

When an atom loses an electron to form a cation, the size typically:

• A. Increases
• B. Remains unchanged
• C. Varies
• D. Decreases

Answer: (D)

Losing an electron creates a cation, and the remaining electrons feel a stronger pull from the nucleus because the same number of protons is now attracting fewer electrons. This increase in effective nuclear charge on the remaining electrons pulls them closer, while there’s less electron-electron repulsion pushing them apart. The result is a smaller electron cloud and a smaller atomic radius. So, when an atom loses an electron, its size typically decreases. For contrast, adding electrons to form an anion would increase repulsion and expand the size.

Losing an electron creates a cation, and the remaining electrons feel a stronger pull from the nucleus because the same number of protons is now attracting fewer electrons. This increase in effective nuclear charge on the remaining electrons pulls them closer, while there’s less electron-electron repulsion pushing them apart. The result is a smaller electron cloud and a smaller atomic radius. So, when an atom loses an electron, its size typically decreases. For contrast, adding electrons to form an anion would increase repulsion and expand the size.