What exactly do you mean by elements 'x', 'y', and 'z'? You can search for an atom on the periodic table by searching for its atomic number, or you can base your search on atomic radius, electronegativity, or ionization energy.
Atomic radius increases as you move down the groups in the periodic table. Electronegativity and ionization energy decrease as you move down the groups, but increase as you move from left to right on the periodic table.
I hope this answered your question! Not entirely sure what you mean by elements x, y, and z.