Atoms
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All substances are made of very tiny particles called atoms
There are about 100 substances that are made up of just one type of atom. These are called
elements
Element
Molecule
Compound
H
x
H2
x
x
H2O
x
x
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Formula-The symbols and numbers that represent the atoms in a substance.
A compound has very different properties to the elements from which it is made
compound – Substance made up of two or more different types of atoms that are chemically
joined together.
immiscible – Liquids which do not mix.
miscible – Liquids which do mix.
mixture – Two or more substances that are mixed but not chemically joined together.
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-Atomic number
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Tells us the number of electrons
Tells us the number of protons
Arranged by increasing Atomic #
Is the smallest number. Usually above the symbol.
Tells us the identity of the element
-Atomic Mass
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Can help find the number of neutrons
Atomic mass= # of protons + # of neutrons
Electrons have no mass
The larger number. Usually found on the bottom if the symbol
-Protons, Neutrons, electrons
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Protons have a positive charge
Electrons have a negative charge
Neutrons have no charge
Know how to draw a model of an atom. Label: Protons, Neutrons, Electrons, Nucleus, and
Electron Shells
Protons Mass- 1 amu
Neutron mass-1 amu
Electron-0
Classified as subatomic particles
-Isotopes
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Different number of Neutrons
Same element
Different types of the same element (atomic mass is different)
3 isotopes of Carbon. Written C-12, C-13, C14
To find the number of Neutrons. # of Neutrons= Atomic Mass - # of Protons or
Atomic Mass- Atomic #
-Physical Properties
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Size Dependent, depends on size, (Weight, Mass, Volume)
Size independent, does not depend on size (Conductivity, Solubility, Boiling/freezing point,
Density
-Separating Mixtures
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Filtering
Boiling point for miscible liquids (liquids that dissolve into each other) also called distillation
Pipette for Immiscible liquids (liquids that do not mix)
Magnetism
Density