Atomic Structure and the Periodic Table

Atomic Structure and the Periodic Table

1. Atoms

   • Central nucleus, composed of protons and neutrons
     • Protons
       • Relative mass
         • 1
       • Relative charge
         • +1
     • Neutrons
       • Relative charge
         • 0
       • Relative mass
         • 1
   • Surrounded by electrons orbiting in shells
     • Electrons
       • Relative charge
         • -1
       • Relative mass
         • 1/1860

2. Atomic number

   • Number of protons=number of electrons
   • Mass number
     • Number of protons and neutrons
   • Isotopes
     • Atoms of an element with the same number of protons but differing numbers of neutrons
   • Relative atomic mass
     • The average mass of an atom of an element taking into account the abundance of its isotopes

3. The Periodic Table is an arrangement of elements in order of atomic number

4. Group

   • Horizontal, how many electrons are in the outer shell
   • Period
     • Vertical, how many shells an atom has

5. Noble gases

   • Group 0
   • A family of inert gases
   • They're un-reactive because they're stable-have a full outer shell of electrons

6. Elements in the same group of the periodic table have similar chemical properties as they have the same number of electrons in their outer shell