The four periodic properties are:-
1)Ionization potential- the amount of energy required to donate or remove an electron from the outermost shell of an atom is called ionization potential
2)Atomic radius:-it is the distance between the nucleus and the outermost shell of an atom.
3)Electron affinity:- it is the amount of energy required to accept an electron from the outer most shell of an atom.
4)Electro negativity:- it is the tendency of an atom to attract electrons towards itself