Question

nonmetallic elements form ions by □ valence electrons to complete their outer shell. the □ valence electrons an element has in its outer shell, the easier it is to complete. the □ electron shells an element has, the easier it is to fill its outermost shell. reactivity in nonmetals □ as you go from left to right in a group, and □ as you go from top to bottom.

Explanation:

1. Nonmetals need to gain electrons to achieve a stable octet (or duplet for hydrogen/helium) in their outer shell. So the first blank is "gaining".
2. The more valence electrons a nonmetal has (closer to 8), the easier it is to gain the remaining electrons to complete the outer shell. So the second blank is "more".
3. The fewer electron shells an element has, the closer the outer shell is to the nucleus, and the stronger the attraction for electrons. So it's easier to fill the outer shell with fewer shells. Thus, the third blank is "fewer".
4. In a group (vertical column) of nonmetals, as we go from left to right (wait, actually groups are vertical; maybe a typo, should be period? But assuming group here as vertical, no—wait, nonmetals: in a period (horizontal), from left to right, nonmetallic character increases, but for reactivity: in nonmetals, within a group (top to bottom), reactivity decreases (since atomic size increases, attraction for electrons decreases). Within a period (left to right), reactivity of nonmetals increases (since more valence electrons, closer to 8, easier to gain). Wait, the question says "from left to right in a group"—maybe a mistake, should be period. But following the logic: nonmetals gain electrons. The more valence electrons (closer to 8), easier to gain. Fewer shells, easier to gain (since nucleus is closer). So reactivity of nonmetals: as you go from left to right in a period (but question says group—maybe a typo, but assuming the intended is period or group as horizontal? Wait, no, groups are vertical. Let's correct: in nonmetals, reactivity increases as you go from left to right in a period (because more valence electrons, closer to 8, easier to gain) and decreases as you go from top to bottom in a group (because atomic size increases, valence electrons are farther from nucleus, harder to gain). So the fourth blank (left to right in group—maybe a mistake, but if we take it as period, but the question says group. Alternatively, maybe the question has a typo, but following the electron gain logic: when moving left to right in a group (which is vertical, so same group, left to right doesn't make sense—maybe horizontal, i.e., period). So reactivity in nonmetals "increases" as you go from left to right in a period (or group if horizontal), and "decreases" as you go from top to bottom. So the fourth blank is "increases", fifth is "decreases".

Answer:

1. gaining
2. more
3. fewer
4. increases
5. decreases