Question

question 7
which of the following set of substances are only compounds?
br, ne, mg
ch4, co, hi
u, feo, na
cr, o, no

Explanation:

A compound is a substance made up of two or more different elements chemically combined. In the first option, Br (bromine), Ne (neon), and Mg (magnesium) are elements. In the third option, U (uranium) and Na (sodium) are elements, and FeO is a compound. In the fourth option, Cr (chromium) and O (oxygen) are elements, and NO is a compound. In the second option, CH₄ (methane), CO (carbon - monoxide), and HI (hydrogen iodide) are all compounds as they are composed of different elements.

Answer:

CH₄, CO, HI