Chemistry?

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, meaning they need to gain an electron to reach a stable configuration, and elements on the line are semiconductors.

You are talking about a bond where two elements need to gain one or two electrons. That can only happen by sharing electrons, which we call a covalent bond. NOx would be an example of such a molecule.

A metal bonded to a non-metal is an atom that loses electrons bonded to an atom that needs to gain electrons. A bond is not defined as purely ionic or purely covalent. Bonds might be anywhere along a range running between the two extremes.