Final answer:
Atoms with higher electronegativity have a greater ability to attract electrons in a bond, causing the shared electrons to spend more time around them.
Step-by-step explanation:
When atoms form covalent bonds with each other, the electrons in the bond are not always shared equally. Atoms have different electronegativities, which is their ability to attract electrons. When a covalent bond is formed between two atoms with different electronegativities, the shared electrons spend more time around the nucleus of the atom with the higher electronegativity, making it slightly negative.
For example, in a bond between hydrogen (H) and fluorine (F), fluorine has a higher electronegativity than hydrogen. As a result, the shared electrons spend more time around the fluorine atom, giving it a slightly negative charge. This is because fluorine has a greater tendency to attract electrons in the bond to itself.
Therefore, the electrons spend more time around the 'more nonmetallic' atom because it has a higher electronegativity and a greater ability to attract electrons in a bond.