Question

Under which circumstances would electrons be most likely to be shared equally?

a) when they are equidistant from nuclei
b) when they are equidistant from each other
c) when atoms of the same element are sharing them
d) when the atoms sharing them are different

Answer 1

Equally shared electrons in covalent bonds occur between atoms with similar electronegativities, resulting in nonpolar covalent bonds. Different electronegativities lead to polar covalent bonds with unequally shared electrons.

Step-by-step explanation:

Electrons are most likely to be shared equally between two atoms when they have similar electronegativities. Electronegativity is a measure of an atom's ability to attract and hold onto electrons within a covalent bond. When two atoms with similar or identical electronegativities come together, they exert similar forces on the shared electrons, resulting in a nonpolar covalent bond. This uniform sharing of electrons is what characterizes a nonpolar bond.

Conversely, when atoms with different electronegativities form a covalent bond, the shared electrons are not distributed evenly. The atom with the higher electronegativity will pull the shared electrons closer, creating a polar covalent bond. In this scenario, there is a partial negative charge on the more electronegative atom, and a partial positive charge on the less electronegative atom. An example of this is the bond between hydrogen and oxygen in water, where oxygen, being more electronegative, holds the electrons closer to itself.