answersLogoWhite

0

The vertical columns of the Periodic Table are called groups. The horizontal rows of the periodic table are called periods. The number of electron shells an atom has corresponds to the number period of the periodic table it is located in. The oxidation number or number of valence electrons an atom is depicted by the group it is in.

For example: Calcium (Ca) has an oxidation number of +2 and has 2 valence electrons( outermost electrons) which means it belongs to group 2 of the periodic table called the "alkali earth metals".

User Avatar

Wiki User

15y ago

What else can I help you with?