Describe the difference between a covalent bond and an ionic bond.

An ionic bond if formed from the transfer of electrons from the outer shell of atoms. The donor of the electrons becomes positively charged as it has more protons than electrons, and so is called a cation. The atom that accepts the electrons becomes the anion, as it is negatively charged due to it having more electrons than protons. The formation of the a positive ion and a negatively charged ion forms an ionic bond due to the attraction between the charge of these two ions. An example of this is NaCl, where the sodium atom becomes Na⁺ due to the loss of electrons, and the chlorine atom becomes the negatively charged chloride (Cl^-). More commonly, metal atoms lose electrons and become positively charged, i.e. Na --> Na⁺ + e^-, while non-metal ions tend to gain electrons and become negatively charged, i.e. Cl + e^- --> Cl^-. Ionic compouns tend to have high melting bonds, and are electrical conductors when in the molten form, but not when solid. A covalent bond forms when the electrons in the outer shells of two non-metal atoms are shared. These are strong bonds with take a lot of energy to be broken, and are often found in molecules with low boiling and melting points. This is because the number of electrons in the outershell of each atom is even, and thus the electron charge around each atom is balanced. An example is HCl, where the hydrogen atom, with one electron shares it's electron with a chlorine atom, which has 7 outer shell electrons. Therefore HCl is more balanced than separate hydrogen and chlorine atoms.