Bonding And Physical Properties Flashcards
1
Q
Why does Argon has low m.p ?
A
- Ar is a monatomic noble gas = its single atom has electrons that are close to nucleus = difficult to polarise
- full electron shells = stable, unreactive
2
Q
Trend of m.p of period 3
A
- m.p increase from Na to Al
- silicone has highest m.p
- phosphorus to argon m.p decrease
3
Q
Why is m.p of Na - Al increase ?
A
- nuclear charge increase as more protons -) across period
- smaller atomic radius
- stronger attraction between + ions and delocalised e- = stronger metallic bond
= more energy needed to break the strong bond
4
Q
Why does silicone have the highest m.p in period 3 ?
A
- macromolecular structure = strong covalent bonds = strong electrostatic attraction = more energy needed to break the bond
5
Q
Why does m.p decrease from P- Ar ?
A
- P,S,Cl, Ar are all non metal elements and simple molecular elements of molecular structure
- weak VDW forces that are easy to overcome = less energy needed
6
Q
Why does sulfur has higher m.p than phosphorus ?
A
- S has a larger molecule S8 than P4 = more e- = stronger VDW forces between molecules = more energy needed to overcome the force
7
Q
Explain why it is important to stir the reaction mixture before recording values? (1)
A
- ensures all solution in the flask is at the same temperature
