Question
Sun February 20, 2011 By: Akriti None
wich is the 
a) lightest metalloid? 
b) element wid 1/2 as many as electrons in 4th shell as compared to 3rd shell.
c) element having highest melting point among sodium and sulphur ? why?

urgent

Expert Reply
Sun February 20, 2011
Dear Student
a) Lightest metalloid is boron.
The metalloid are boron, silicon, etc. We know the size increases as we move down a group. So, all other metalloids are larger than boron.
 
b) explain again.
 
c) Mp of sulphur is 386.36 K and that of sodium is 370.87 K. 
 
Reason---- It is the van der Waals’ forceswhich is responsible for the low melting point of sulphur. when sulphur melts, the van der waals forces between the molecules are broken. These are very weak bonds. So, little energy is needed to overcome them.
 
We hope that clarifies your query.
Regards
Team
Topperlearning
Ask the Expert