Ions

IonsIon- An Ion is a charged atom. The atom can have a charge of positive or negative. For an atom to have a positive charge the atom must lose an electron, metals will have the positive charge. For an atom to have a negative charge the atom must gain an electron, nonmetals with have the negative charge. Atoms use their outer electrons to join. The outer electrons on an atom gives the atom its chemical properties. One way atoms can join is to transfer one or more electrons from one atom to another. When an electron transfers from one atom to another the atoms no longer be electrically neutral. Atoms have equal number of positive charges (protons) in the nucleus and negative electrons. When the atom loses an electron it becomes a positively charged ion. When the atom gains an electron it becomes a negatively charged Ion. The positive and negative ions will attract to one another. The atoms want to have a full outer electron shell. For example a Lithium atom (Li) has an electron arrangement of 2,1. The outer electron shell is 1. For this atom to have a full outer shell it must get rid of the one electron. Once rid of the 1 electron, its only shell has 2 and cannot have any more electrons. The atom is now a positive ion and has a full outer electron shell. Now, a oxygen atom (O) has an electron arrangement of 2,6. The outer shell has 6 electrons. For this atom to get a full outer electron shell it must gain two electrons. The atom is now a negative ion and has a full outer electron shell. Metals lose electrons, whilst non metals gain electrons. METALS FORM POSITIVE IONS. NON-METALS FORM NEGATIVE IONS. Forming IonsThe valency of an element in an ionic compound is the same as the number of electrons lost or gained. This means that the valency is the same as the charge on the ion. The valency of an atom = the size of the charge of its ion Valency Ion charge 2 2+Example. Mg ------> Mg the 2 of Mg is the valency. 2+ is the ion charge. A table below will show you the Valency of each group. I will allow you to work out the ion charge