Question

What trend does the reactivity of most nonmetals show in a periodic table, excluding the noble gases?

random changes without any trends on the periodic table
changes according to trends on the periodic table
increases from left to right across the periodic table

Answer 1

increases from left to right across the periodic table

Explanation: Electronegativity and electron affinity generally increase across a period, so nonmetals become more eager to gain electrons (more reactive) moving left→right (e.g., fluorine is the most reactive nonmetal). Reactivity of nonmetals generally decreases down a group.