11. which compounds shown represent molecules containing covalent bonds? check all that apply.
- calcium bromide
- methyl bromide
- ethylene bromide
- potassium bromide

Methyl bromide

Ethylene bromide

Explanation:

Calcium bromide - It is made of an electropositive atom of Calcium and 2 electronegative atoms of Bromine. Therefore, the Calcium atom loses 2 electrons and the bromine atoms gain an electron each, thus forming Ca(2+) ion and Br(1-) ions. These result in electrostatic forces pf attraction between the Ca ion and Br ions, thus forming an ionic bond.Methyl bromide - it contains a Bromine atom attached to a Carbon atom. The carbon atom is neither electronegative nor electropositive. Hence, there won't be any formation of ions as in the case with calcium bromide. But the bromine atom would still have a partial negative charge(due to it's electronegativity) and the Carbon atom would have a partial positive charge, but this isn't enough for a complete ionic bond and hence, the molecule has predominantly covalent bonds.Ethylene bromide - Similar case as above (methyl bromide). Bromine atom attached to a carbon atom doesn't form any ionic bond, but forms a covalent bond.Potassium Bromide - Similar to calcium bromide. Electropositive atom of potassium interacting with the electronegative atom of bromine, results in the formation of ions and hence, ionic bond.

Note that in general, a bond between an electropositive element (s block elements) and electronegative element (like group 16,17,18) is ionic.

Copper, silver, aluminum, cobalt, chromium, mercury