What is the difference between the atomic number and the mass number of an
element?

The major difference between atomic number and mass number is that the atomic number states the number of protons present in an atom whereas, the mass number indicates the total of the number of protons and the number neutrons present in an atom.

Explanation:

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.