U1-2-1 - Covalent Radius Flashcards
Part of the Periodicity topic from Unit 1 of Higher Chemistry, Chemical Changes and Structure
1
Q
Half the distance between the centres of two covalently joined atoms
A
Covalent radius
2
Q
Covalent radius ________ going down a group.
A
increases
3
Q
Covalent radius ________ going across a period.
A
decreases
4
Q
Explain why covalent radius increases going down a group.
A
The number of occupied energy levels (e− shells) increases.
5
Q
Explain why covalent radius decreases going across a period.
A
Increase in nuclear charge
6
Q
Why does an increase in nuclear charge make the covalent radius decrease?
A
Outer electrons are more strongly attracted to the nucleus
This causes electrons to be pulled closer to the nucleus
7
Q
Why is the covalent radius of aluminium larger than its ionic radius ?
A
More occupied energy levels
Al is 2,8,3 (3 occupied E levels) and Al3+ is 2,8 (2 levels)
