Is an element and a compound heterogeneous?

NO!!!

Elements and compoounds exists as separate entities.

Heterogeneous means a mixture of substances that are in different physical states.

Compare to Homogeneous which means a mixture of substances that are in the SAME physical state.

However, The element bromine(Br) is liquid at STP. The compound water(H2O) is also a liquid at STP. When mixed together to form bromin water, it is an homogeneous mixture.