Question

you do: 1) which of the following has the same number of electrons as cl⁻? a) f⁻ b) s c) al³⁺ d) k⁺

Explanation:

Step1: Find electrons in \( \text{Cl}^- \)

Chlorine (Cl) has atomic number 17, so Cl atom has 17 electrons. \( \text{Cl}^- \) gains 1 electron, so electrons in \( \text{Cl}^- \): \( 17 + 1 = 18 \).

Step2: Analyze each option

• Option a: \( \text{F}^- \)

Fluorine (F) has atomic number 9. \( \text{F}^- \) gains 1 electron: \( 9 + 1 = 10 \) electrons. Not 18.

• Option b: \( \text{S} \)

Sulfur (S) has atomic number 16, so S atom has 16 electrons. Not 18.

• Option c: \( \text{Al}^{3+} \)

Aluminum (Al) has atomic number 13. \( \text{Al}^{3+} \) loses 3 electrons: \( 13 - 3 = 10 \) electrons. Not 18.

• Option d: \( \text{K}^+ \)

Potassium (K) has atomic number 19. \( \text{K}^+ \) loses 1 electron: \( 19 - 1 = 18 \) electrons. Matches \( \text{Cl}^- \).

Answer:

d) \( \text{K}^+ \)