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