Answer:
The atomic number is the number of protons in the nucleus and also the number of orbiting electrons. The mass number is the number of protons and neutrons in the nucleus.
The mass number minus the atomic number is the number of neutrons in the nucleus.
An isotope will have a different atomic mass.
<span>A.) the Appalachian Mountains</span>
Answer is: (4) proton and neutron.
One unified atomic mass unit is approximately the mass of one nucleon (proton or neutron).
The unified atomic mass unit (amu) is a standard unit of atom mass.
One unified atomic mass unit is approximately the mass of one nucleon (1.66·10⁻²⁷ kg).
For example, one carbon atom has mass of 12 amu (unified atomic mass).
The electron has a mass that is approximately 1/1836 that of the proton.