1. Introduction to Atoms: Atoms are the basic building blocks of matter. They consist of subatomic particles- protons, neutrons, and electrons.

2. Protons: Positively charged particles found in the nucleus of an atom. Protons have a relative charge of +1 and a mass of approximately 1 atomic mass unit (amu).

3. Neutrons: Neutral particles found in the nucleus of an atom. Neutrons have no charge (neutral) and a mass of approximately 1 amu.

4. Electrons: Negatively charged particles that orbit the nucleus of an atom in electron shells or energy levels. Electrons have a relative charge of -1 and a negligible mass compared to protons and neutrons.

5. Atomic Number (Z): The number of protons in the nucleus of an atom. It determines the identity of the element and its place in the periodic table.

6. Mass Number (A): The sum of the number of protons and neutrons in the nucleus of an atom. It represents the mass of the atom.

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7. Isotopes: Atoms of the same element with different numbers of neutrons. Isotopes have the same atomic number but different mass numbers.

8. Atomic Mass Unit (amu): A unit of mass used to express atomic and molecular weights. 1 amu is approximately equal to the mass of a proton or neutron.

9. Relative Atomic Mass: The weighted average of the masses of the isotopes of an element, taking into account their relative abundances in nature.

10. Fundamental Forces: Subatomic particles interact through fundamental forces such as electromagnetic force, strong nuclear force, weak nuclear force, and gravitational force.

11. Subatomic Particle Arrangement: Electrons are arranged in electron shells or energy levels around the nucleus. The distribution of electrons follows specific rules such as the Aufbau principle, Pauli exclusion principle, and Hund's rule.

12. Quantum Numbers: Parameters that describe the properties of electrons in an atom including principal quantum number (n), azimuthal quantum number (l), magnetic quantum number (m), and spin quantum number (s).

In conclusion, the study of subatomic particles in class 11 chemistry provides a foundational understanding of the basic constituents of matter. Through the exploration of protons, neutrons, and electrons, students gain insight into the structure of atoms and the principles that govern their behaviour. By comprehending the roles and interactions of these subatomic particles, learners lay the groundwork for more advanced topics in chemistry, enabling them to appreciate the complexity and diversity of the elements in the periodic table. Ultimately, the knowledge acquired about subatomic particles serves as a cornerstone for further exploration into the realms of chemical bonding, reactions, and the broader field of chemistry.