melting and boiling points Flashcards
1
Q
m+b point increase across …
A
group 1 - 4
2
Q
m+b decrease across …
A
5-0
3
Q
m+b point increase as (why) …
A
metallic bond strength increases
+ metal ion gets smaller across period
charge gets larger more delegalised electron
stronger attraction between + ion and - delegalised electrons
4
Q
elements g4
A
carbon, silicon both high m+b point
both have giant covalent or macromolecular structure
with many strong bonds
5
Q
elements g5 - 0
A
simple molecules or weak van der walls force between them.
