Dalton’s Atomic Model

John Dalton• September 7, 1766 – July 27, 1844• An English chemist, physicist and

meteorologist• One of the pioneers of the development of the

modern atomic theory• Daltonism – it is the concept of Dalton’s

research about color blindness

John Dalton• In 1803, he published his first table on relative

atomic weights. He computed the atomic weights from the percentage composition of compounds

• He also contributed on Gas Laws

John Dalton’s Atomic Theory1. Elements are made of extremely small particles called

atoms.2. Atoms of a given element are identical in size, mass,

and other properties; atoms of different elements differ in size, mass, and other properties.

3. Atoms cannot be subdivided, created, or destroyed.4. Atoms of different elements combine in simple whole-

number ratios to form chemical compounds.5. In chemical reactions, atoms are combined, separated,

or rearranged.

BILLIARD BALL MODEL

Billiard Ball Model• Dalton’s atomic model• Created in 1803• Represented as a tiny indivisible uniformly dense, solid

sphere• Elements are comprised by tiny particles called “atoms”• Atoms can’t be divided, destroyed or created• Atoms of two or more elements combine to form a

compound• Has no nucleus• Become the basis for future atomic model

Billiard Ball Model• Atoms are of the same size and same

component as the element• Dalton thought that atoms are empty inside