Understanding Matter
0 Matter is anything that has mass and takes up
space
0 Everything is matter. {Exceptions—light,
magnetism}
0 An atom is a small particle that is a building block
of matter
Atoms
0 Atoms have 3 parts
• protons
• neutrons
• electrons
o At the center of an atom is a nucleus. The nucleus
has a positive charge.
o Protons have a positive charge and are found
in the nucleus.
Atoms
o Neutrons have no charge (neutral) charge and are
found in the nucleus.
o Electrons have a negative charge and are found in
the electron cloud
o An atom is almost too small to imagine.
Atomic Structure
There are two basic components in every atom:
Electron Cloud
Nucleus
Subatomic Particles
Electron Cloud:
• Electrons orbit the
nucleus.
Nucleus or “Core”:
• Protons and
Neutrons are found
in the nucleus.
Subatomic Particles
Three subatomic particles make up every atom:
Subatomic Particle
Charge
Location
Proton
Positive (+)
Nucleus or “Core”
Neutron
No Charge (0)
Nucleus or “Core”
Electron
Negative (-)
Electron Cloud
Atoms
0 Matter is anything that takes up space and has mass.
All matter is made of atoms.
0 Atoms are the basic building blocks of matter. They
make up everything around us; Your desk, the board,
your body, everything is made of atoms!
0 Atoms are too small to see without powerful
microscopes.
Substances
oA substance is matter with a
composition that is always the
same.
oThis means that a given
substance is always made of the
same combination(s) of atoms.
Elements
oAn element is a substance that
consists of just one type of atom
oatomic number--the number of
protons in an atom
oatomic mass--the number of protons
and neutrons in an atom (Round
atomic mass to nearest one.)
Elements
oProtons = Atomic Number
oFor an atom to be neutral, number of
protons = number of electrons
oNeutrons = Atomic Mass (Rounded
to nearest 1) – Atomic Number
oSymbol stands for the element. One
capital letter or one capital letter
and lower case letter.
Elements
oThe most basic unit of
matter is the element!
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