How does a difference in electronegativity determine the type of bond between
elements?

A high difference in electronegativity will be present in ionic compounds since the electrons are transffered from the element less electronegative to the element more electronegative.

A small difference in electronegativity is present in molecular compounds (covalent bonds). None of the elements is strong enough to attract the electrons so the electrons are shared.

Explanation:

A high difference in electronegativity will be present in ionic compounds since the electrons are transffered from the element less electronegative to the element more electronegative.

A small difference in electronegativity is present in molecular compounds (covalent bonds). None of the elements is strong enough to attract the electrons so the electrons are shared.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.