B.Sc. 1st Year – Inorganic Chemistry Notes
Topic: Atomic Structure
Subject Code: CHEM-101
1. Introduction to Atomic Structure
An atom is the smallest unit of matter that retains the properties of an element.
Atomic structure refers to the composition of atoms: electrons, protons, and neutrons.
2. Subatomic Particles
Particle Symbol Charge Mass (approx)
Electron e⁻ -1 9.1 × 10⁻³¹ kg
, Proton p⁺ +1 1.67 × 10⁻²⁷ kg
Neutron n⁰ 0 1.67 × 10⁻²⁷ kg
3. Models of the Atom
a) Dalton’s Atomic Theory (1803):
Matter is made of indivisible atoms.
Atoms of the same element are identical in mass and properties.
b) Thomson’s Model (1897):
Topic: Atomic Structure
Subject Code: CHEM-101
1. Introduction to Atomic Structure
An atom is the smallest unit of matter that retains the properties of an element.
Atomic structure refers to the composition of atoms: electrons, protons, and neutrons.
2. Subatomic Particles
Particle Symbol Charge Mass (approx)
Electron e⁻ -1 9.1 × 10⁻³¹ kg
, Proton p⁺ +1 1.67 × 10⁻²⁷ kg
Neutron n⁰ 0 1.67 × 10⁻²⁷ kg
3. Models of the Atom
a) Dalton’s Atomic Theory (1803):
Matter is made of indivisible atoms.
Atoms of the same element are identical in mass and properties.
b) Thomson’s Model (1897):
