Ionic bonds are formed when two positively charged ions (cations) or two negatively charged ions (anions) interact with one another. The interaction between the two ions creates a new, more stable molecule with a lower energy level. This new molecule is called an ionic bond. Ionic bonds are very strong and can resist breaking apart even under harsh conditions. In fact, ionic compounds are some of the most durable substances on Earth!
What are ions?
Ions are atoms that have gained or lost an electron. When atoms gain electrons, they become negatively charged ions (anions). When atoms lose electrons, they become positively charged ions (cations). If one ion gains or loses one or more electrons, it has 1+ charge; if the atom gains or loses two or more electrons, it has 2+ charge; if the atom gains or loses three or more electrons, it has 3+ charge.
The number of lost or gained electrons determines which sign an ion carries and its overall charge:
Cations: positive (+)
Anions: negative (-)
Example: Na +
Neutral Sodium atom loses an electron to become a positively charged sodium ion, Na+. The atom’s overall charge becomes (+1).
Example: Cl –
A neutral Chlorine atom gains an electron to become a negatively charged chloride ion, Cl-. The atom’s overall charge becomes (-1).
When atoms gain Chlorine atom gains an electron to become a negatively charged chloride ion, Cl-. The atom’s overall charge becomes (-1).
What happens when two ions are brought together?
When two ions of the same type are brought together, they will bond or repel with one another. This typically occurs when there is an attractive force between the atoms that causes them to be more stable together than apart. Additionally, the electrons in the cation and anion’s outermost energy levels become correlated, leading to a lower total energy level for both ions.
In ionic bonds, the atoms lose their separate identity as individual atoms and combine to form a new substance with properties different from those of its component elements. In their ionic compounds, they are no longer Cl- and Na+, but appear as NaCl.
Ionic compounds are made of positive and negative ions, which have strong electrostatic forces attracting them to each other. They are extremely hard due to this force of attraction between the two oppositely charged ions in their crystal lattice structure. The forces of these interactions is so great that ionic compounds are often found as crystals, rather than molecules.