ELECTRON – negative, mass nearly nothing

PROTON – positive, same mass as neutron

(“1”)

NEUTRON – neutral, same mass as proton

(“1”)

The Ancient Greeks used to believe that everything was made up of very small particles. I did some experiments in 1808 that proved this

and called these particles ATOMS:

Dalton

A diagram showing the location of each part of the atom.

A diagram showing the location of each part of the atom.

Diagram of an Atom

diagram showing the charges of each part of the atom.

Describe NeutronNeutrons are uncharged particles found in

the atomic nucleus. Neutrons were discovered by James Chadwick in 1932.

Experiments done in the late 1960's and early 1970's showed that neutrons are made from other particles called quarks. Neutrons are made from one 'up' quark and two 'down' quarks.

Describe ProtonProtons are positively charged particles

found in the atomic nucleus. Protons were discovered by Ernest Rutherford..

Experiments done in the late 1960's and early 1970's showed that protons are made from other particles called quarks. Protons are made from two 'up' quarks and one 'down' quark.

Describe Isotope

Atoms that have the same number of protons but

different numbers of neutrons

Describe IsotopeExample:

Mass and atomic numberParticle Relative Mass Relative Charge

Proton 1 1Neutron 1 0Electron 0 -1

MASS NUMBER = number of protons + number of neutrons

SYMBOL

PROTON NUMBER = number of protons (obviously)

presented by :- Purushottam

Barde(Roll no. 122)