Question

A pure substance made up of only one type of atom is a(n)
A. mixture.
B. element.
C. compound.
D. proton or neutron.

Answer 1

A pure substance that is made up of only one type of atom is B.
An element.

Answer 2

Answer: element

Explanation:

Element is a pure substance which is composed of similar or one type of atoms.It can not be decomposed into simpler constituents using chemical reactions.Example: Gold $Au$

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: carbon dioxide $CO_2$

Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present. Example: air