electronegativity question

[pharmd09]

So I;m studying the first few chapters of general chemiistry from my kaplan book and I came across some information I needed clarificatication on.

Based on the reading I found that:

nonpolar covalent bonds: 0 to 0.4
polar covalent is: 0.4 to 1.7
ionic bonds: 1.7 and greater

I was also going through my old gen chem notes and my teacher said

nonpolar covalent: 0 to 0.5
polar covalent: 0.5 to 1.9
ionic: 1.9 and greater

I know its not a MAJOr difference in ranges. but sometimes it can be pretty vague if we had to differentiate betweem a nonpolar and polar covalent bond. ionic is pretty easy cause it is just a matter of balancing charges.

Does anyone have a more exact idea of what the electronegativity ranges are?

Thanks

 

[NewRx]

The closer the elements from (group 4-7), the more covalent they are. On PCAT test, you will not be asked such trivial questions as to the range of covalent bonds.