Using the periodic table, select two main group sets of elements (suggestion: pick group 1 or 2 and group 15, 16, or 17). Describe any trends in electronegativity and first ionization energy in each group. Explain these trends.

For group 1 elements, the electronegativity of the elements decrease as one move down the group. This is because the increased energy level of the elements put the outer electrons far away from the attractive pull of the nucleus of the elements. Electronegativity increases as one move across the period from left to the right. For group 15 elements also, electronegativity decreases down the group.

For group 1 elements, the first ionization energy decreases down the group. This is because, as the atomic radius increases, the negatively charged electron is moved further away from the positively charged nucleus, thus it is less attracted to the nucleus and the energy needed to remove it becomes less. The same is true for group 15 elements, their first ionization energy decrease down the group.