Final Answer:
Magnesium (Mg) has 8 valence electrons. Therefore, the correct option is c. 8.
Step-by-step explanation:
Magnesium (Mg) has 2 valence electrons. In the periodic table, the number of valence electrons corresponds to the digit in the one's place of the group number. Magnesium is in Group 2, and the one's place digit is 2, indicating 2 valence electrons.
Valence electrons are crucial in determining an element's chemical properties and its ability to form bonds. In the case of magnesium, having 2 valence electrons makes it likely to lose those electrons to achieve a stable, noble gas electron configuration.
When magnesium loses its 2 valence electrons, it forms a positively charged ion (Mg²⁺), becoming stable with an electron configuration similar to that of neon. This tendency to lose electrons is a characteristic of metals in Group 2 of the periodic table. Therefore, the correct option is c. 8.