Ionic vs Covalent

[Carolina Lechuga]

During lecture we were told that if the electronegativity difference was greater than 2 then it was and ionic bond but if it was less than 1.5, it was a covalent bond. However, in my discussion we were told that if it was <0.4 it was covalent, between 0.4 and 1.8 was polar covalent, and greater than 1.8 was an ionic bond. My question is did I copy one of these wrong or whats the true measurements?

[Jocelyne Milke 1G]

I'm not sure about the second part but the first part is correct. In my notes I also have that if the electronegativity difference is greater than 2 it is ionic and if it is less than 1.5 it is covalent.

[Daniel Kim 1D]

The book helps attest for the first part, but honestly there is probably some leeway to the numbers because of each elements bond length and/or other factors but I think it’s safe to think 2 and 1.5, easier to memorize as well!