Question

for nonmetals, as you go down a group, the reactivity __________; as you go across the period, the reactivity ___________.
decreases; decreases
increases; increases
decreases; increases
increases; decreases

Explanation:

• For non - metals, as you go down a group, the atomic size increases. The outermost electrons are farther from the nucleus, so the attraction for incoming electrons (which is related to non - metal reactivity as non - metals tend to gain electrons) decreases. So reactivity decreases down a group.
• As you go across a period (from left to right), the atomic size decreases (due to increased nuclear charge without a significant increase in the number of electron shells). The non - metals on the right side of the period have a greater tendency to gain electrons (since they are closer to achieving a full valence shell), so reactivity increases across a period.

Answer:

C. Decreases; Increases