Final answer:
The atoms that will share electrons when a bond is formed between them from the options is D. Br and Cl, which form a covalent bond. Unlike ionic bonding in compounds like LiCl, bromine and chlorine share electrons to form a molecule with a covalent bond.
Step-by-step explanation:
The pair of atoms that will share electrons when a bond is formed between them from the given options is D. Br and Cl. This is because both bromine (Br) and chlorine (Cl) are nonmetals and tend to form covalent bonds by sharing electrons in order to achieve a full valence electron shell.
Covalent bonds are formed by two nonmetal atoms sharing electrons. For example, each Cl atom in a Cl2 molecule interacts with eight valence electrons: the six in the lone pairs and the two in the single bond. This type of bonding is different from ionic bonding, where there is a complete transfer of electrons from one atom to another, typically between a metal and a nonmetal, resulting in the formation of positive and negative ions.
In the case of BeCl2 and LiCl, the bonding differ because LiCl forms ionic bonds, with Li+ cations and Cl− anions, while BeCl2 forms covalent bonds with shared electrons between Be and Cl atoms due to the fact that beryllium is a group 2 element and has a stronger tendency to form covalent bonds.