Anions More electrons than protons, so negatively-charged. Each electron shell can hold a specific number of electrons. The first can hold 2 electrons, the second shell can hold 8, the next 8, etc. Ionic One atom gives away one or more electrons to another atom. Covalent One atom shares some of its electrons with one or more other atoms.
Covalent bonds are typically stronger than ionic bonds.
For example, the carbon atoms which make up diamond are bonded to each other with covalent bonds, and diamonds are the hardest minerals. H 2 O. Hydrogen has one proton and one electron, while oxygen has 8 protons and 8 electrons. Here is a diagram of water showing the covalent bond. Metallic Bonding style found in metals. Electrons are only loosely bound to any specific nucleus, and so can flow freely from one nucleus to the other.