Inside An Atom
Nucleus
Every Atom has a core called a nucleus.
 The Nucleus is largest part of an atom
(about 99.9% of it’s mass)
 Within the nucleus are very small particles
called protons and neutrons
 Electrons are in an orbit around the
nucleus

Protons
Protons are the positively charged
particles found inside the nucleus of an
atom
 Every element has a unique atomic #.
This # is the amount of protons inside that
elements nucleus
 For Example: Oxygen has an atomic # of
8. How many protons does it have?
8

Neutrons
Neutrons are the other particle found
inside the nucleus of an atom
 Neutrons have no charge
 Atoms of a same element may not carry
the same number of neutrons

Electrons
Negatively charged particles found orbiting
around the nucleus
 Electrons are very small; only about
1/2000th the mass of a proton or neutron
 Electrons can move between atoms which
causes bonds; this is how new compounds
are formed
