Question

what is the correct electron configuration of phosphorus (p)? a. 1s²2s²2p⁶2d⁵ b. 1s²2s²2p³3s²3p³ c. 1s²2s²2p⁶3s¹3p⁴ d. 1s²2s²2p⁶3s²3p³

Explanation:

Step1: Recall phosphorus atomic number

Phosphorus has atomic number 15, so 15 electrons.

Step2: Apply electron - filling rules

Electrons fill orbitals in order of increasing energy: 1s, 2s, 2p, 3s, 3p. 1s can hold 2 electrons, 2s can hold 2 electrons, 2p can hold 6 electrons, 3s can hold 2 electrons and 3p can hold 6 electrons. Filling the orbitals for 15 electrons gives $1s^{2}2s^{2}2p^{6}3s^{2}3p^{3}$.

Answer:

D. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{3}$