Question

epsom salt (mgso₄·7h₂o) is commonly used in baths to reduce pain and muscle fatigue. when put in water, epsom salt dissociates into mg²⁺ and so₄²⁻ ions. which of the following is the correct lewis diagram for the mg²⁺ ion? choose 1 answer: a mg²⁺ b ·mg·²⁺ c mg²⁺

Explanation:

Step1: Recall Lewis - diagram rules for ions

Lewis diagrams for ions show the symbol of the element in brackets with the charge outside. For a cation, the atom has lost electrons. Magnesium (Mg) is in Group 2 of the periodic table. A neutral Mg atom has 12 electrons with an electron - configuration of 1s²2s²2p⁶3s². When Mg forms a Mg²⁺ ion, it loses 2 electrons from its outer shell (3s²). So, there are no valence electrons left for Mg²⁺.

Step2: Evaluate the options

Option A: $[\text{Mg}]^{2 + }$ is the correct Lewis diagram for the Mg²⁺ ion as it simply shows the Mg symbol in brackets with the 2+ charge outside, indicating the loss of 2 electrons. Option B and C show dots around the Mg symbol, which would imply the presence of valence electrons. But Mg²⁺ has lost its 2 valence electrons, so these are incorrect.

Answer:

A. $[\text{Mg}]^{2 + }$