A carbon atom has four valence electrons. The number of valence electrons of any atom of an element can be determined by the period table group in which the element is classified. There are a total of 18 groups on the period table group.
The carbon atom is in group 14 of the periodic table of elements. It has a valence electron configuration of 2s2 2p2. This group is termed as the carbon group, and it consists lead, silicon, tin and germanium.
Group one atoms have one valence electron, and group two atoms have two valence electrons. Group 13 has three valence electrons.