Key Points on Periodicity

Question 1

Shielding

Answer 1

As you go down the group:
* Sheilding increases
* Increase in shells bt/w nucleus + outer shell
* Less attraction

Constant when you go across period

Question 2

Nuclear Charge

Answer 2

When increase in protons = stronger attraction bt/w nucleus + outer electron

Increases when go across period + down group

Question 3

Define Ionisation Energy

Answer 3

Energy required to remove a mole of electrons from a mole of gaseous atoms.

Question 4

Describe the trends going down a group?

Answer 4

Decrease in:
* Electronegativity
* Attraction bt/w nucleus BP

Increase in:
* Shielding
* Atomic radius

Question 5

What must you talk about when discussing trends in reactivity?

Answer 5

• Size: atomic radius + shielding
• Attraction
• Ionisation energy

Question 6

What are the trends across a period?

Answer 6

Decrease in:
* Atomic radius

Increase in:
* Nuclear charge
* Electronegativity
* Ionisation energy (general)

Shielding constant

Question 7

What must you talk about when discussing trends/differences in MPs?

Answer 7

• Amount electrons
• Type of intermolecular forces/bonding
• Amount energy required break forces

Question 8

Describe trends going down G2?

Answer 8

Decrease in:
* MP
* Metallic bonding gets weaker due increase in ion size
* Ionisation energy - despite increase nuclear charge, it decreases due to the increase in shielding

Increase in:
* Reactivity
* Atomic radius
* Shielding