in the periodic table elements in the same group have the same what?

Elements in the same group have the same number of valence electrons.

In the periodic table, elements in the same group have the same number of valence electrons. Valence electrons are the electrons found in the outermost energy level of an atom. Elements in the same group have similar chemical properties as a result of having the same number of valence electrons, which determines how they interact with other atoms to form bonds.