Question
25. How many valence electrons are in an atom of magnesium? a. 5 b. 3 c. 4 d. 2
Answer
4
(385 Votes)
Nigella
Elite · Tutor for 8 years
Answer
d. 2
Explanation
Valence electrons are the electrons in the outermost shell of an atom and are involved in bonding reactions. These electrons are extremely useful in facilitating the formation of chemical bonds with other atoms. The atomic number of magnesium is 12 which indicates that a neutral atom of magnesium has 12 electrons. The number of valence electrons in an atom is determined by its electron configuration, which is split into energy levels. The electrons on the highest energy level, or the outermost energy level, are the valence electrons. The Electron configuration of Magnesium is 2,8,2. Hence, Magnesium has 2 valence electrons.