Ionic bonding The bond of opposite charges holding ions together. Forms between atoms with significantly different electronegativites. If there is small electronegativit y difference between atoms a covalent bond will most likely form. The compounds formed are electrically neutral. They are held by electrostatic attracti on of oppositely charged ions. Formation of ions Cations form when an electron is lost. There are more protons than electrons so it is positively charged. They form from metal atoms, because they have low ionization energies, meaning that electrons are easily lost. Anions form when an electron is gained. There are more electrons than protons resulting in it being negatively charged. They form from non metal atoms, because they have high ionization energies and high electronegativities. This means that they will be less likely to loose electrons and more likely to gain them. Positive ions are smaller and negative ions are bigger than the parent atom. Cations loose valence electrons, meaning they have one less shells, so are smaller. Anions gain electrons in the outer shell meaning that there are more forces of repulsion and the electrons move away from each other, increasing radius. Ions form in order for the atom to have full outer shells, reaching the noble gas electronic configuration. Giant i onic lattice Ions bond together forming a giant lattice with a repetitive pattern. Cations are surround by the anions, and they can be in different ratios. They are held together by bonds, which keep them in place so a structure is formed They vibrate around a fixed position Isoelectreonic ions Eg. N3-,O2-,…,Al3+They have identical electronic configuration, however they differ in size. N3- is the biggest in the group, and Al3+ is the smallest. This is the result of all of them having the same negative charge from outer electronis, but different positive nuclear charge from the protons. Al3+ has the highest nuclear charge, and the most protons, so the electrons on its outer shell will experience the highest attractive force. This mean that they will be more tightly held, resulti ng in a smaller radius of the ion. Conductivity
