Question

Which of the following ground-state electron configurations represents the atom that has the lowest first-ionization energy?

A) 1⁵² 2s¹
B) 1⁵² 2⁵² 2p²
C) 1⁵² 2s²²p⁶
D) 1⁵² 2⁵² 2p⁶ 3⁵¹

Answer 1

The atom with the lowest first-ionization energy will have the most stable electron configuration. Option C, 1⁵² 2s²²p⁶, represents the atom with the lowest first-ionization energy.

Step-by-step explanation:

The atom with the lowest first-ionization energy will have the most stable electron configuration. In general, elements with fully filled electron shells or half-filled subshells tend to be more stable. Looking at the options:

1. Option A, 1⁵² 2s¹, has a completely filled 1s orbital and a singly occupied 2s orbital. This is a stable configuration.
2. Option B, 1⁵² 2⁵² 2p², has a completely filled 1s orbital, a completely filled 2s orbital, and two electrons in the 2p orbital. This is also a stable configuration.
3. Option C, 1⁵² 2s²²p⁶, has a completely filled 1s orbital, a completely filled 2s orbital, and a completely filled 2p orbital. This is a very stable configuration.
4. Option D, 1⁵² 2⁵² 2p⁶ 3⁵¹, has a completely filled 1s orbital, a completely filled 2s orbital, a completely filled 2p orbital, and five electrons in the 3s orbital. This is also a stable configuration.

Based on the above analysis, option C, 1⁵² 2s²²p⁶, represents the atom with the lowest first-ionization energy. It has a fully filled 2p orbital, making it highly stable.