For nonmetals, how does chemical reactivity trend in a group?
It increases down a group.
It decreases down a group.
It depends on the group of nonmetals being considered. The group 17 elements (halogens) generally exhibit an increase in chemical reactivity down the group. On the other hand, group 18 elements (noble gases) generally have very low chemical reactivity and do not follow a clear trend down the group.
It decreases down a group.
The correct answer is that chemical reactivity generally decreases down a group for nonmetals. Here's how to arrive at this conclusion:
To understand chemical reactivity trends in a group, we need to look at the periodic table. In a group, elements have similar outer electron configurations because they have the same number of valence electrons. In the case of nonmetals, these valence electrons are involved in chemical reactions.
As we go down a group, the valence electrons are located in higher energy levels or shells. This means that they are farther from the positively charged nucleus and experience weaker attraction. Therefore, these electrons are less likely to be involved in chemical reactions because they are more stable and less reactive.
On the other hand, if we move across a period from left to right, the trend is generally that chemical reactivity increases. This is because as we move from left to right, the number of valence electrons remains the same, but the effective nuclear charge increases due to the increasing number of protons in the nucleus. This stronger attraction between the nucleus and the valence electrons makes the electrons more reactive and more likely to participate in chemical reactions.
In summary, for nonmetals, chemical reactivity tends to decrease down a group because the valence electrons are located in higher energy levels and experience weaker attraction to the nucleus.