Circle the most polar molecule. A. H2O b. NH3 c. HF Justification: __________

Question

A.H2O B. NH3 C. HF

Justification: __________

Answer 1

C. HF

Fluorine is the most electronegative element on the Periodic Table. In the 2p shell of Fluorine it has 5 electrons. There is a big electronegativity difference between H and F as opposed to the H and O and N and H. Also, there is a high partial negative on F.

Notice as you go from left to right, and go up the groups on the periodic table the electronegativity increases (excluding noble gases because they have a stable electron configuration and NO electronegativity)? That means there is more nuclear charge and less shielding of electrons. Fluorine has a lot of charge in its nucleus. The electrons are packed closely to the nucleus, and the atom has the best ability to attract electrons.