Which of the following provides the best explanation for the chemical similarities between sodium and potassium?
A:Both are solids at room temperature.
B:Both have the same number of occupied energy levels
C;Both have one valence electron.
D:Both have average atomic masses between 20 and 40 amu.

C ;Both have one valence electron.

Explanation:

Elements classified to be in the same group in the periodic table possess the same number of valence electrons. This means that they will react the same way with other elements as they require the same number of electrons to fill their electron shell.

This is the case of sodium (Na) and potassium (K) which both belongs to group 1. This means that they have one valence electron in their outermost shell. Hence, this accounts for the reason they both will behave chemically similar to one another.

let that person have a turn to speak : )

there are two significant figures.