PIC MODULE 2

Atoms

Smallest unit of matter; building blocks of matter.

Subatomic particles

Proton, Neutron, Electron

Proton

Positively charged particle located in the nucleus.

Neutron

Particle with no charge located in the nucleus.

Electron

Negatively charged particle located in the electron shell.

Neutral atom

Contains equal numbers of protons and electrons, resulting in no charge.

Positively charged atom

Nucleus of the atom contains protons only.

Democritus

Proposed that all matter consists of indivisible particles called atomos.

John Dalton

Formulated the Billiard Ball Model, defining atoms as solid spheres.

J.J

Proposed the Raisin-Bread Model, discovering electrons embedded in a positive sphere.

Ernest Rutherford

Introduced the Nuclear Model through the Gold Foil Experiment, discovering the nucleus.

Niels Bohr

Developed the Planetary Model, describing electrons moving in circular orbits around the nucleus.

Erwin Schrodinger

Introduced the Quantum Mechanical Model, describing electrons moving in a 3D electron cloud structure.

James Chadwick

Discovered the neutron by bombarding Beryllium with alpha particles.