Question

What characteristic shared between chlorine, fluorine, and bromine makes them have similar properties?

A. All have seven valence electrons.
B. All have the same number of protons in their outermost energy levels.
C. All have two electrons in their first energy levels.
D. All have a similar state of matter.

Answer 1

The Correct Answer is A. If you look at the periodic table of elements, you may notice that Chlorine (Cl, #17), Fluorine (F, #9), and Bromine (Br, #35) are all in the same family (or column). That is group VIIA or 17. VII is 7 in roman numerals and that is the number of valence electrons.

Hope that helps!