Download O: You will be able to explain how atoms make up the world.

O: You will be able to
explain how atoms make
up the world.
Do Now: What do you know
about atoms?
What is an atom?


Atom- a small particle
that makes up most
matter.
They are so small a
piece of human hair is
1,000,000 thick.
How small are they?

If you held an orange in
your hand and wanted
to see the individual
atoms, you would have
to make the orange the
size of the Earth.
Early Ideas about Atoms



The word atoms comes from the Greek word
Atomos which means “cannot be divided”
Each type of matter has its own atom.
Atoms are like very tiny marbles that are held
together by a force.
What makes up atoms?



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Atoms are made of
three types of particles:
Protons
Neutrons
Electrons
Protons



Atomic sub-particles
Protons have a positive charge. (+)
Protons are found in the nucleus of the atom
Neutrons



Atomic sub-particles
Neutrons have a neutral charge (no charge)
(o)
Found in the nucleus
Electrons



Atomic sub-particles
Electrons have a negative charge. (-)
They are found outside the nucleus of the
atom.
Homework questions



If atoms are round, how come everything in
the world is not round?
What are the three sub-particles that make
up atoms?
Why are atoms neutral?