Question

Use the images to answer the question.

An illustration shows elements of group 1 from least reactive at the top to most reactive at the bottom as Li, Na, K, Rb, Cs, and Fr.

An illustration shows elements of group 17 from least reactive at the bottom to most reactive at the top as At, I, Br, Cl, and F.

Which of the following combination of elements is the most reactive?

(1 point)
Responses

Ccapss andIcaps
C caps s and I caps

Ccapss and Bcapsr
C caps s and B caps r

Ncapsa and Bcapsr
N caps a and B caps r

Kcaps and Icaps
K caps and I caps

Answer 1

Cs and Br.

Reactivity of group 1 increases down the group (Cs is more reactive than K or Na). Reactivity of group 17 increases up the group (Br is more reactive than I). So Cs + Br is the most reactive pair among the options.