Fill in the blank.
elements in a family have the same
a. level of reactivity
b. protons and neutrons
c. number of valence electrons

Number of valence electrons

Explanation:

A family of elements is defined as a specific group of those elements. Groups in the periodic table are identified by columns, e. g., group 1A contains alkali metals, group 2A contains alkaline earth metals, group 7A consists of halogens, group 8A contains noble gases etc.

The group number corresponds to the valence electrons these atoms have. The number of protons for each atom is different and the level of reactivity depends on the size of the atom mainly, as well as electronegativity.

C the same number of valence electron

Explanation:

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.