9.

Periodic Table of Elements

Answer the question below. View the periodic table of elements linked above for help if needed.

How can the periodic table be used to determine the number of valence electrons of a given element?

The rows of the periodic table indicate the number of valence electrons of a given element. For example, aluminum is found in the third row of the periodic table; therefore, aluminum has three valence electrons.

The groups of the periodic table indicate the number of valence electrons of a given element. For example, beryllium is in the second group of the periodic table, so beryllium has two valence electrons.

The periods of the periodic table indicate the number of valence electrons of a given element. For example, hydrogen is found in the first period, so hydrogen has one valence electron.

The number of valence electrons corresponds to the atomic number of the element. For example, helium has the atomic number of two. Therefore, helium has two valence electrons.

The groups of the periodic table indicate the number of valence electrons of a given element. Elements in the same group have the same number of valence electrons. For example, all elements in Group 1 (the alkali metals) have one valence electron, and all elements in Group 17 (the halogens) have seven valence electrons.