The number of valence electrons of an atom is typically equal to which of the following?

The number of valence electrons in an atom is typically associated with the group number in the periodic table. Elements in the same group share similar chemical properties and have the same number of valence electrons. For example, the elements in Group 1 (alkali metals) have one valence electron, while those in Group 2 (alkaline earth metals) have two valence electrons. This grouping can be used to predict how these elements will react chemically and their bonding behavior.

In contrast, the atomic number represents the total number of protons in the nucleus of an atom, which is not directly related to the number of valence electrons. The period number indicates the highest energy level that an electron occupies, which does not provide specific information about the number of valence electrons. Lastly, the total number of electrons in a neutral atom is equal to the atomic number, but this total includes core electrons in addition to valence electrons, making it unsuitable for determining the number of valence electrons specifically.