[xleftranx]

hi
Im new here.
and i wanna ask whether all charged molecules are polar?
such as NH4+. Is it polar?
if yes,why,if no,why?
thanks

[Dan]

1) Draw a 3D representation of the ammonium ion.
2) Draw vectors for all the polar bonds.
3) Sum these vectors.
4) The resultant vector is your molecular dipole.

eg. CO₂

1)  O=C=O
2)  <--  -->
3) Vectors cancel out exactly, ie. Sum to 0
4) No resultant vector, non polar.

Try this for NH₄⁺, do you find that the ammonium ion is polar?