Structure of Atom
5.0 Atomic Number and Mass Number and It's Relation
5.0 Atomic Number and Mass Number and It's Relation
Atomic Number
- The number of protons present in the nucleus is equal to atomic number $(Z)$.
- Atoms are identified by their atomic number.
- In order to keep the electrical neutrality, the number of electrons in an atom is equal to the number of protons (atomic number, $Z$ ).
Atomic number $(Z)$ = number of protons in the nucleus of an atom
= number of electrons in a neutral atom
Mass Number
The mass of the nucleus, due to protons and neutrons.
mass number $(A)$ = number of protons $(Z)$ + number of neutrons $(n)$
Protons and neutrons present in the nucleus are collectively known as nucleons.
