Answers (1)
You do have a printed periodic table, right? You can get the information at www.chemicalelements.com/index.html but you really need your own printed copy to carry with you. It will be a primary reference for everything you do.
There is a diagonal line, B-C, Si-P, Ge-As, Sb-Te, and Po-At. Elements to the left of the line are metals, meaning they lose an electron easily, elements to the right of the line are non-metals, and elements on the line are semiconductors.
As far as I have studied them, all compounds of two non-metals are covalent.