Isotopes and Ions

• Isotopes are atoms of the same element with different number of neutrons.They have the same atomic number, but different mass number.
• What does the atomic number represent?

  The number of protons in an atom's nucleus.
• What does the atomic mass represent?

  it reflects the sum of the number of protons and neutrons.
• How do you calculate the number of neutrons?

  Atomic mass - atomic number.
• Number of protons = number of electrons
• Ion is an electrically charged particle formed by losing or gaining one or more electrons from its outer shell.
• if electrons have been loss a positive ion ( cation) will form
• if electrons have been gained a negative ion (anion) will form.
• Metals-Example:(E =Electron),(P=Proton)

  Na+9 means that..

  Atom. ion

  (E)=11. 2

  (P)=11. 11

  The electron loses because +9 represent that 9 positive ion have been added as the electrons have been loss.
• Non Metals-Example (E-electron), (P=proton)

  O-2

  Atom. ion

  (E)= 8. (E)=10

  (P)=8. (P)=8

  The electron ganes two negative ions as the electrons have been loss but the atomic number stays
• 1. Atomic number
  2. Element symbol
  3. relative Atomic mass