Final answer:
The commonality between He, Ne, Ar, Li, C, F, and Br is their pursuit of a stable electron configuration like that of noble gases, through chemical bonding to satisfy the octet rule.
Step-by-step explanation:
The elements He, Ne, Ar, Li, C, F, and Br have in common their tendency to achieve a stable electronic configuration that is similar to that of the noble gases.
Helium (He), Neon (Ne), and Argon (Ar) are noble gases with full valence electron shells, making them inert or non-reactive under normal conditions. Lithium (Li), Carbon (C), Fluorine (F), and Bromine (Br) are all representative elements that seek to achieve a noble gas electron configuration by gaining, losing, or sharing electrons.
This is known as the octet rule, where elements aim to have eight electrons in their valence shell through chemical bonding. Li, along with Na, K, Rb, and Cs, are alkali metals from Group 1, which form halide compounds such as LiCl, NaCl, KCl, RbCl, and CsCl in a 1:1 ratio with halogens to achieve this stable configuration.