Chemistry Regents Practice Test

How do the valence electrons of metals in Period 3 compare to those of nonmetals in Period 3?

1. They have more valence electrons.

2. They have fewer valence electrons.

3. They have the same number of valence electrons.

4. They do not have valence electrons.

The correct answer is: They have fewer valence electrons.

In Period 3 of the periodic table, metals such as sodium (Na), magnesium (Mg), and aluminum (Al) typically have three or fewer valence electrons. For example, sodium has one valence electron, magnesium has two, and aluminum has three. In contrast, nonmetals found in Period 3, like sulfur (S) and chlorine (Cl), have five or more valence electrons. Specifically, sulfur has six valence electrons, while chlorine has seven. This difference arises from their positions in the periodic table: metals are located on the left side, while nonmetals are on the right. As you move from left to right across a period, the number of valence electrons increases. Therefore, the valence electrons of metals in Period 3 are fewer than those of nonmetals in the same period, making this the correct answer.