Download Atomic Structure

Atomic Structure
Atom, Bohr-Rutherford, and the
Periodic Table
A New Order
• Atomic Number – how many protons and electrons there are in
an atom
• Mass Number – total number of protons and neutrons.
• Atomic Mass Units – atomic mass does appear on the periodic
table and is measured in u.
– Not measured on a balance, it is how they are relative to each other
– A proton is about 1u, a neutron is about 1u and an electron is 1/1837 in
relation to protons and neutrons
Looking Forward
• Atomic number
– Helps to define arrangement of periodic table
– Relates to chemical properties of elements
– Relates to arrangement of electrons
– Group 1 – how many electrons are in outer
(valence) shell?