Numerical answer · +4 / −1
The maximum number of electrons that can be accommodated in the valence shell of carbon is x.
Answer and solution
Answer 8
Solution
Chemistry ma’am · 4 steps
Carbon's valence shell is n = 2, so ask what that shell can hold, not what carbon puts in it.
- Find the shell. Carbon has 6 electrons, arranged as 2 in the first shell and 4 in the second. Its valence shell is the outermost one, n = 2.
- Use the capacity rule. A shell with principal quantum number n can hold at most 2n² electrons.
2n² = 2 × 2² = 8
- Check by subshells. The n = 2 shell has one 2s orbital and three 2p orbitals. That makes 4 orbitals, each holding 2 electrons, so the shell holds 8.
- So. The valence shell of carbon can hold at most 8 electrons, so x = 8.
The common slip: 4. Giving the number of electrons carbon actually has in its valence shell gives 4, not the shell's capacity of 8.
The idea to keep. The maximum a shell can hold depends only on n: it is 2n². How many electrons an atom actually has in that shell is a separate question.
Answer from the NTA final answer key. Solution by PrepWiser.