7.1 - The periodic table

Question 1

What is periodicity?

Answer 1

A repeating trend in properties of the elements

Question 2

What is the periodic trend in electron configuration? (blocks)

Answer 2

S, P, D ,F blocks

Question 3

What group was missing from Mendeleev’s periodic table and suggest why he was unaware of it

Answer 3

Group 0 contains the very unreactive noble gases, and no elements from that group had been discovered at the time

Question 4

What is the trend in atomic radius across a period?

Answer 4

It decreases
- The number of protons increases in the nucleus
- The attraction between the electrons and the nucleus becomes stronger
- This draws the electrons closer to the nucleus
- Causing atomic radius to decrease

Question 4

What is the trend in atomic radius down a group?

Answer 4

It increases
- The number of electron shells increases down a group
- The outer electron shell is further from the nucleus
- This increases the amount of shielding between the nucleus and the outer electron
- There is less attraction between the outer electrons and the nucleus
- Causing atomic radius to increase