Question

which of the following substances is made up of only one type of atom? a)hydrogen (h₂) b)carbon (c) c)water (h₂o) d)carbon dioxide (co₂)

Explanation:

Elements are substances made up of only one - type of atom. Hydrogen ($H_2$) is a molecule of an element, but it is made of two hydrogen atoms. Oxygen ($O_2$) is a molecule of an element, made of two oxygen atoms. Carbon dioxide ($CO_2$) is a compound made of carbon and oxygen atoms. Carbon ($C$) is an element and is made up of only carbon atoms.

Answer:

b) Carbon (C)