Subatomic Particles
Atomic Number and Protons
*Atomic Number - the number of protons in an atom.
*Proton (p+) - positively charged subatomic particles in the nucleus of an atom.
# of Protons identifies the element
Electrons (e-)
-- negatively charged subatomic particles that
orbit the nucleus
*Neutral atom (no charge), # of protons = # of
electrons
*Charged atom (ion), electrons have been
gained or lost
Cation - positively charged ion where electrons
have been lost
Anion - negatively charged ion where electrons
have been gained
Atomic Mass or Mass Number
-- the mass of an atom is equal to the number of protons plus the number of
neutrons
Neutrons (n0) -- neutral subatomic particle that is located in the nucleus
●
the # of neutrons is calculated by subtracting the # of protons from the
atomic mass
Isotopes
-- atoms of the same element with different numbers of neutrons
●
●
the atomic mass is calculated as an average atomic mass that includes the
average of the isotopes for that element with the frequency they are found
Isotopes are named with the element name or symbol and the mass of that
isotope
OR
X - mass number
Changing an Atom
Ion
ATOM
Add or Subtract a Proton
Add or
Subtract an
Electron
Add or
Subtract a
Neutron
Isotope
Add Another
Atom
Molecule
New
Element