Atomic Structure

Atomic Structure

1. Protons

   • Positively charged
     • Found in nucleus
     • +1
   • 1 amu
   • This is the Atomic Number
     • The Periodic Table is arranged in increasing atomic number

2. Electrons

   • Negatively charged
     • -1
   • 1/1840 amu
   • Orbit the nucleus in shells
     • 1st shell has a maximum of 2 electrons
       • 2nd shell holds a maximum of 8 electrons
         • 3rd shell holds a maximum of 8 electrons
     • The outer shell gains or loses electrons
       • The atom becomes an ion
         • The ion has the same structure as a noble gas

3. Neutrons

   • The Mass Number is neutrons + protons
     • To find the number of neutrons, take the Atomic Number from the Mass Number
   • 1 amu
   • Neutral (no charge)
     • 0
     • Found in nucleus