Question

choose the complete ground - state electron configuration for neutral rubidium (rb). ar 4s2 3d10 4p5; 1s2 2s2 2p6 3s2 3p6; kr 5s2; kr 5s1

Explanation:

Neutral rubidium (Rb) has an atomic number of 37, meaning it has 37 electrons. Krypton (Kr) has an atomic number of 36, so its electron configuration accounts for 36 electrons. Rubidium, being in group 1 of the periodic table, has one additional electron in the 5s orbital. The option [Kr] 5s¹ adds this single electron to Kr's full configuration, totaling 37 electrons for neutral Rb. The other options have incorrect electron counts: [Ar] 4s2 3d10 4p5 has 35 electrons, 1s2 2s2 2p6 3s2 3p6 has 18 electrons, and [Kr] 5s2 has 38 electrons.

Answer:

[Kr] 5s1