Ionic Compounds/Bonding?

Question

I've checked all over my chemistry textbook, but I just can't find the answers to these questions (they're phrased awkwardly too)
For Ionic compounds:
Here's what the question says. Electronegativity difference is ____ (________________) 1.67. (yeah, I have no idea what that's asking) For example, an atom with _________ electronegativity (___________) and one with a electronegativity (_______________).

Can someone explain electronegativity difference, the textbook just confused me.

Here's another about ionic compounds, under "Forms"
No molecules - ions are arranged in ____________ __-___ patterns to form ___________________.

I am so confused--the teacher hasn't taught us anything on this subject!

Thank you so much for any help, if you can't answer the questions, maybe you could just explain what you know that seems to be related to the question.

Thanks again!

Answer 1

more than.........3.0......... / .7 /
you must have something that gives you a list of EN differences right?
EN is basically how much an atom wants to gain an electron so metals have low EN's and non-metals have high EN's
the difference is jus one minus the other. if the number comes out more than 1.67 it is ionic.if it is in between 0 and 1.67 is is polar and if the EN difference is 0 than it is non-polar.
excited-state / compounds