Fundamentals of Atomic Structure and Discoveries

Dalton's theory

Atoms of different elements combine to form compounds in fixed ratio.

Plum - pudding model

Thomson model

Alpha particles

Positively charged helium nucleus.

Goldstein

Who discovered protons?

Thomson

Who discovered electrons?

Rutherford

Who discovered the nucleus?

Chadwick

Who discovered neutrons?

Rutherford's experiment

Rutherford fired alpha particles at gold foil.

Charges of electrons

Negative

Charges of protons

Positive

Charges of neutrons

Neutral

Nucleus particles

Particles in the nucleus are protons and neutrons.

Electrons location

Particles outside the nucleus are electrons.

Atomic numbers and protons

Atomic numbers and protons are fixed for an element.

Mass number

Number of protons and neutrons in an atom is its mass number.

Atomic number

Atomic number is the number of protons and electrons.

Nucleus size

Size of the nucleus is very small as compared to the size of an atom.

Cathode ray

Glowing beam from cathode.

Cathode

Positive electrode.

Anode

Negative electrode.