Lesson 5: Periodicity and Ionisation Energy

Question 1

Periodicity

Description

Answer 1

Term to describe repeating patterns seen on the periodic table.

Question 2

Periodicity

Trends

Answer 2

Physical and chemical properties across a period and down a group can be related to atomic structure.

Question 3

Atomic Radii

Description

Answer 3

• The size atom or ion is determined by its nuclear pull and electron shielding.
• Nuclear Pull: attraction between the nucleus and outer electrons.
• Electron Shielding: repulsion of outer electrons by inner electrons.

Question 4

Atomic Radii

Across a Period

Answer 4

• The number of protons increases across a period so the nuclear pull increases.
• As the number of shells stay the same, the electron shielding stays constant.
• Outer shell electrons are closer to the nucleus, decreasing atomic radius.

Question 5

Atomic Radii

Down a Group

Answer 5

• The number of protons increases down the group so the nuclear pull increases.
• This attracts more electrons, leading to greater electron shielding.
• Outer shell electrons are repulsed, increasing atomic radius.

Question 6

Ionisation Energy

First Ionisation

Answer 6

• A measure of the amount of energy needed to remove electrons from atoms.
• Eg. Na(g) ~> Na+(g) + e-

Must include state symbols

Question 7

Ionisation Energy

Second Ionisation

Answer 7

• Energy required to remove the second electron.
• Eg. Na+(g) ~> Na++(g) + e-

Must include state symbols

Question 8

Ionisation Energy

Factors

Answer 8

• Atomic Radius.
• Nuclear Charge.
• Electron Shielding.