Question

Classify nuclei on the basis of atomic number and mass number and define them.

Hint:

The atomic number determines the chemical identity of the element, while the mass number helps to classify different isotopes and their stability.

Answer 1

Nuclei can be classified based on their atomic number (\(Z\)) and mass number (\(A\)) as follows: 1. **Atomic Number (\(Z\))**: The atomic number represents the number of protons in the nucleus and is denoted by \(Z\). It determines the chemical properties of the element and its position in the periodic table. Nuclei with the same atomic number belong to the same element. 2. **Mass Number (\(A\))**: The mass number is the total number of protons and neutrons in the nucleus and is denoted by \(A\). It gives the approximate mass of the nucleus. Different isotopes of the same element have the same atomic number (\(Z\)) but different mass numbers (\(A\)) because they have different numbers of neutrons. Types of Nuclei Based on \(Z\) and \(A\):
- **Isotopes**: Nuclei with the same atomic number (\(Z\)) but different mass numbers (\(A\)) are called isotopes. They have the same number of protons but different numbers of neutrons. Example: \({}^1_1H\) (protium) and \({}^2_1H\) (deuterium). - **Isobars**: Nuclei with the same mass number (\(A\)) but different atomic numbers (\(Z\)) are called isobars. Example: \({}^4_2He\) (helium) and \({}^4_1H\) (hydrogen). - **Isotones**: Nuclei with the same number of neutrons but different atomic numbers and mass numbers are called isotones. Example: \({}^4_2He\) and \({}^3_1H\). - **Isomers**: Nuclei with the same atomic number (\(Z\)) and mass number (\(A\)) but different energy states are called isomers. They are the same element but in different nuclear states.