No it isn't.
Salt, because is a chemical compound - NaCl; uranium, boron, hydrogen are chemical elements.
The base word in "belong" is "long."
No, building is not a compound word.
Choose the word that does not belong
Proteins .
The contraction (not a compound word) is doesn't.
Upwards is a compound word.
There is no compound word.A compound word is a word like bus-stop.Husban is spelt like this husband
The keyword belongs to the alkene series compound.
Upstairs is a compound word, so it is one word.
Mango is not a compound word.
It cannot be a compound word.