periodic trends :@ (1 Viewer)

[planino]

How would I explain the trend for melting and boiling points across a period and a group, and to what depth?
I'm struggling to describe it consisely.

Also, do we need to mention the strength of intermolecular forces as well in our answer?

The entire 8.3.3 dotpoint is driving me crazy

 

[planino]

bump

 

[such_such]

Straight from my dot points:

• ACROSS A PERIOD
- Moving left to right, we observe a general transition from metals to semi-metals to non-metals; there is a structural transition from metallic to covalent network lattices, to covalent molecules
- Metallic lattices have metallic bonds, which are strong attractions between cations + delocalised electrons
- In covalent network lattices, the covalent bonds, which the electrons are shared, are even stronger
- Covalent molecules only have weak intermolecular forces
- This variation gives rise to the trend: INCREASES (up to Group IV) then DECREASES

• DOWN A GROUP
- Metals – metallic bonds (attractions between cations + delocalised electrons)
- Strength of metallic bonds decreases down a group because the valence electrons are further away
- Non metals – have dispersion forces (a type of weak intermolecular force); these increases with greater molecular mass
DECREASES for metals but INCREASES for non-metals

 

[planino]

Holy shizzle, they're excellent!

Thanks