Answer:
The correct answer is "Element A is more reactive".
Explanation:
The missing options of this question are:
Element A is more reactive.
Element A is less reactive.
Element A and B have the same reactivity.
Element A has no reactivity.
The correct answer is "Element A is more reactive".
Valence electrons are defined as outer shell electron that can participate in the formation of chemical bonds with other atoms. The atoms tend to have either 0 or 8 valence electrons. Therefore, depending in the number of valence electrons, an atom can either give their valence electrons (1 to 3 electrons) or try to take more valence electrons (4 to 7 electrons). Element A with 7 valence electrons is more reactive that Element B with 4 valence electrons, because Element A only needs 1 more electron to full its 8 valence electrons.
