Explanation:
Elements in the same group have the same number of valence electrons. Across a period left to right number of valence shell electrons increases but in the group this trend remains same means number of valence shell electrons are constant.
The atomic radius is increases from top to bottom in the group and decreases from left to right across a period.
Ionization enthalpy or energy increases across a period and decreases down the group. Ionization energy is the energy that requires to remove the outermost electron from the subshell.
Electronegativity decreases down the group because atomic number increases down the group and increases across a period.
