2025 Chemistry Unit 3 (AS.1)

Atoms

Democritus

Greek philosopher (said if you keep cutting something it will eventually be uncuttable)

Aristotle

greek philosopher and disagreed with Democritus (said matter is continuous not smaller particles)

Atom

Smallest particle that an element can be divided into and still be that element

Law of conservation

mass is neither created nor destroyed it is only rearranged

law of definite proportions

Atoms must combine in whole number ratios

Law of multiple proportions

Atoms can combine in different whole number ratios

1782 - Lavoisier

Law of conservation

1799 - Proust

Laws of definite and multiple proportions

1751 - Ben Franklin

Law of electrical charges

Law of electrical charges

opposite charges attract like charges repel

1839 - Michel Faraday

Structure and electricity are related

Merie Curie

Radioactivity

1927 - Hiesenburg Uncertanty Principal

more precicly electron position is known

1924 - Lous de Brogle

Electrons act like waves

1803

Dalton’s Atomic Model

Dalton´s Atomic Model

1896

Thomson’s Plum Pudding Model

Thomson’s Plum Pudding Model

1913

Bohr’s Energy level model

Bohr’s Energy level model

1926

Schrodinger’s Quantum Mechanical Model

Schrodinger’s Quantum Mechanical Model

Cathode Ray Experiment

Showing that Some Atoms contain some negatively charged particles called electrons

Gold Foil Experiment

An atom is mostly made up of space. The nucleus is small and surrounded by electrons

Rutherford’s Nuclear Model

1911

Rutherford’s Nuclear Model