Can I predict if a compound has ionic bonds or covalent bonds? If so, how?

Bonds formed between non-metals are generally covalent bonds.

Ionic bonds can ONLY be formed with a cation and an anion. Generally, these ions come from a metal (cation) and a non-metal (anion), but you should also include polyatomic ions, e.g. #"SO"_4^(2-)#, #"NH"_4^(+)#, etc.

I am using "cations" and "anions" to refer to the components in the compound. It does not necessarily have to be elements.

This is because electrons get transferred from the anion to the cation. This transfer results in a strong bond between the atoms and tend to result in properties such as high melting point and a high boiling temperature.

You can determine an ionic compound by calculating its electronegativity (between bonded atoms) - #1.7+# (where #1.7# is barely ionic).

Covalent bonds occur when components in the compound share their electrons.

"Unlike ionic bonds, covalent bonds are often formed between atoms where one of the atoms cannot easily attain a noble gas electron shell configuration through the loss or gain of one or two electrons. In such cases, it is easier to ‘share’ valence electrons." (http://cyberbridge.mcb.harvard.edu/bonding_3.html).

You can determine a covalent compound by calculating the difference in electronegativity

• #0.0-0. 4 ->#non-polar covalent bond OR
• #0.5-1.6 -># polar covalent bond
  (#0.5# is barely polar covalent).

Hope this helps :)