a level chemistry

can someone explain to why PH3 has permeant dipole . i know that to for something to be dipole there must be a difference in electronegativity however how am i meant to know the electronegativity of phosphorus and decide if the difference in electronegativity is large enough to be dipole permeant.

Reply 1

TypicalNerd

Original post by nnn121337

Since PH3 is a compound of two elements, you can say with a fair degree of certainty that there is going to be an electronegativity difference (because there aren’t many elements that have the same electronegativity values) and you can assume that the electronegativity difference will be sufficient for the molecule to have a dipole (if and only if the shape allows that to be the case).

You can also use the general electronegativity trends to predict whether H or P is more likely to be the more electronegative element. (i.e what area of the periodic table typically has the most electronegative elements?)

Next, consider the shape of the molecule:

-If the molecule has a shape in which the bonds do not face opposing directions (e.g bent, trigonal pyramidal, T-shaped), it will be polar.

-In instances where the bonds do face opposing directions (e.g if the molecule has a linear, trigonal planar, tetrahedral, trigonal bipyramidal or octahedral shape), it will be non-polar.

Reply 2

Blue3542

do temporary dipoles distort the atom, as in would the electron cloud look more disfiguredand or expand, or does the electron cloud remain within its own high probability shape?