Question

You have three elements, A, B, and C, with the following electronegativity values:
A= 0.9
B= 3.0
C= 3.5

You react the elements to form the substances AB, AC, and BC. Answer the following questions:
- What type of substance is AB? What types of bonds are present? Explain
- What type of Substance is AC? What types of bonds are present? Explain
- What type of substance is BC? What types of bonds are present? Explain
- If any of the substances are ionic compounds, which elements is the cation and which is the anion? Explain
I don't understand this at all! Please help me!

Answer 1

you have to calculate the difference in polarity between the two elements that form the compound and according to that you can classify the compound and its bonds as ionic, covalent polar or covalent nonpolar. check the link below
http://www.chemteam.info/Bonding/Electroneg-Bond-Polarity.html

Answer 2

1. If the electronegativity difference (usually called ΔEN) is less than 0.5, then the bond is nonpolar covalent.
2. If the ΔEN is between 0.5 and 1.6, the bond is considered polar covalent
3. If the ΔEN is greater than 2.0, then the bond is ionic.
That, of course, leaves us with a problem. What about the gap between 1.6 and 2.0? So, rule #4 is:

4. If the ΔEN is between 1.6 and 2.0 and if a metal is involved, then the bond is considered ionic. If only nonmetals are involved, the bond is considered polar covalent.