The electronegativity of Nitrogen is 3.0 and of chlorine is 3.2.
I am not sure about the exact values. anybody knows the actual
values.
There are multiple systems of electronegativity ratings using
different experimental systems and calculation methods. As such,
you will come across different systems (eg. Pauling, Mulliken,
Allred–Rochow, Sanderson, Allen, etc) giving you different
electronegativity values for each element. Some systems rate Cl as
being more electronegative than N, while other systems rate N as
being more electronegative than Cl.
For A level purposes, N is regarded as more electronegative than
Cl, and as such, only NH groups (in addition to HF and OH groups),
and not HCl, are considered capable of donating H bonds.
A level students are not expected to memorize electronegativity
values from any particular system. Cambridge may give
electronegativity values (from any of the different
electronegativity systems) in the A level question itself, to
examine if the A level candidate is able to interpret the relative
values of the various elements. For instance :
Carbonyl sulfide has the formula O=C=S. If the electronegativity
of O, C and S are 3.5, 2.5 and 2.4 respectively, which bond is more
polar? The O=C bond or the C=S bond? Indicate the partial charges
and dipoles on the O=C=S molecule.