Give the ground-state electron configuration for each of the following elements. After each atom is its atomic number in parentheses. (a) Potassium (19) (b) Neon (10)How many electrons are in the valence shell of each atom ? (a) Visited um (AI) (b) Oxygen (O) (c) Fluorine (F)

(a) ₁₉K: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹

(b) ₁₀Ne: 1s² 2s² 2p⁶

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(a) 3

(b) 6

(c) 7

Explanation:

We can state the ground-state electron configuration for each element following Aufbau's principle.

(a) ₁₉K: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹

(b) ₁₀Ne: 1s² 2s² 2p⁶

Second part

(a) Al belongs to Group 13 in the Periodic Table. It has 13-10=3 electrons in the valence shell.

(b) O belongs to Group 16 in the Periodic Table. It has 16-10=6 electrons in the valence shell.

(c) F belongs to Group 17 in the Periodic Table. It has 17-10=7 electrons in the valence shell.