Question

1. choose the best answer.

for alkali metals, how does reactivity trend in a group?
it decreases down a group.
it increases down a group.

1. choose the best answer.

for nonmetals, how does chemical reactivity trend in a group?
it increases down a group.
it decreases down a group.

Explanation:

• For alkali metals (metals), as we go down the group, the atomic size increases. The outermost electron is more loosely held (due to increased distance from the nucleus and shielding effect). So, it is easier to lose the electron, increasing reactivity down the group.
• For non - metals, as we go down the group, the atomic size increases. The ability to gain electrons (since non - metals tend to gain electrons in reactions) decreases because the outermost shell is farther from the nucleus and the electron - attracting power of the nucleus is reduced. So, reactivity (in terms of gaining electrons) decreases down the group.

Answer:

1. B. It increases down a group.
2. B. It decreases down a group.