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Atomic Theory
MATTER
Mixtures
Pure Substances
Physical Change
Mechanical
Mixtures
Solutions
Compounds
Elements
Chemical Change
Pure Substances
• Pure substances can be divided into 2 groups:
Compounds and Elements.
• Compounds are pure substances that are made
up of two or more different elements.
• Elements in a compound are chemically bonded
to each other and exist in a specific ratio that
is always the same.
• Ex: H2O
Elements
• An element is a pure substance
made up of one type of particle, or
atom.
• Each element has it’s own
properties and cannot be broken
down into simpler substances by
means of chemical change.
Atoms
• Atom: All matter is made up of
atoms. Atoms are the smallest unit
of an element that maintains the
properties of that element.
• http://www.brainpop.com/science/m
atterandchemistry/atoms/
Compounds and Molecules
• Molecule: Composed of 2 or more
elements that are joined by chemical
bonds.
• The elements in a molecule can be the
same (H2, O2) or the elements can be
different.
• All compounds are molecules, but not all
molecules are compounds!!
Compounds and Elements
• The properties of a compound are
different than the properties of the
elements that make it up.
Dalton’s Atomic Theory
1. All matter is made up of small
particles called atoms.
2. Atoms cannot be created,
destroyed, or divided into smaller
particles.
Dalton’s Atomic Theory
3. All atoms of the same element are
identical in mass and size, but are
different in mass and size from
other elements.
4. Compounds are created when
atoms of different elements link
together in definite proportions.