Ionisation Energy

Ionisation Energy

1. Ionisation

   • It is the loss or gain of electrons

2. Energy needed to form positive ions

3. First Ionisation Energy

   • It is the energy required to remove 1 electron from each atom in 1 mol of gaseous atoms to form 1 mol of gaseous 1+ ions.

4. Second Ionisation Energy

   • It is the energy required to remove 1 electron from each atom in 1 mol of gaseous 1+ ions to form 1 mol of gaseous 2+ ions.

5. Tips

   • A) State the state as gaseous B) Mention (1mol of atoms) C) greater I.E easier to loose electron D) Lesser I.E harder to loose electrons

6. Affected by 3 things

   • Nuclear Charge
   • Electron Shielding
   • Atomic Radius

7. Successive I.E

   • E.g. 2nd I.E-- Na+(g) > Na2+(g) + e-
   • E.g. 3rd I.E-- Na2+(g) > Na3+(g) + e-

8. Trend in Periodic Table

   • Across a Period
     • Increases
   • Down a group
     • Decreases