Download Atomic Mass

Atomic Mass
Atomic Mass
• Each element found on the periodic table of
elements is given an atomic mass
• The atomic mass tells you the average mass of
the atoms of an element
• Atomic mass varies from element to element
Atoms
• Atoms of an element are made up of protons,
neutrons and electrons
• Protons are found in the nucleus and have a
positive charge
• Neutrons are found in the nucleus and have a
neutral (no) charge
• Electrons are found outside the nucleus and
have a negative charge
Atomic Mass and Atomic Number
• The atomic mass and atomic number for an
element on the periodic table can help you
determine how many protons, neutrons and
electrons an atom of an element has
Atomic Number and Atomic Mass
Atomic number
Atomic mass
Finding Protons, Neutrons and
Electrons
• Atomic number= the
number of protons and
the number of electrons
in an atom of an
element
• Mass number
(rounded)= number of
protons + number of
neutrons (mass of all
particles in the nucleus
of an atom)
So…
• Oxygen has a total of:
– 8 protons
– 8 electrons
– 8 neutrons
• 15.999 rounded= 16
• 16-8=8