Early Ideas About Matter

Atoms are indivisible and indestructible.

Atoms of a given element are identical in size, mass, and chemical properties. 

Empty space cannot exist. 

Different atoms combine in whole-number ratios to form compounds. 

Mass is conserved in any process.  

The total number of atoms of each element is the same before and after the reaction. 

New atoms are created in a chemical reaction.

It led to acceptance of Dalton’s atomic theory.  

They had few tools for scientific exploration.

They formulated explanations based on their own life experiences.

Many concluded that matter was made of earth, water, air, and fire.

They tested the validity of their ideas with the scientific method. 

nucleus

proton

neutron

electron

Neutron

Photon

Electron

Proton

Atoms are made of protons and electrons.

Atoms can be divided into smaller particles.

Atoms of the same element are identical.

Atoms are created during chemical reactions.

Atoms combine in simple whole-number ratios to form compounds.

Atoms can be destroyed in chemical reactions.

Atoms of different elements have different properties.

Atoms are mostly empty space.

Aristotle

Dalton

Democritus

Plato

Electron

Neutron

Proton

Photon

Atoms of different elements can combine to form compounds.

Atoms are made of smaller particles called quarks.

Atoms have a positive charge in the nucleus.

Atoms can be created or destroyed in chemical reactions.