The nucleus of a hydrogen atom consists of
A
1 proton only
B
1 proton + 2 neutron
C
1 neutron only
D
1 electron only
Correct Answer: 1 proton only
Most hydrogen atoms have nuclei that consist of a single proton, but a small fraction (about 0.015 percent) of the hydrogen atoms that occur in Nature have one neutron in addition to the proton in their nuclei.