Ionic Bonding: Videos & Practice Problems

Ionic bonding is a fundamental concept in chemistry that begins with understanding ions, which are atoms or molecules that carry a net electrical charge. This charge can be either positive or negative, resulting from the gain or loss of electrons, which are negatively charged particles. There are two primary types of ions: anions and cations.

Anions are negatively charged ions formed when an atom gains one or more electrons. The increase in the number of electrons compared to protons results in a net negative charge. For example, when a neutral hydrogen atom, which has one proton and one electron, gains an additional electron, it becomes an anion. This can be remembered by the multiple 'n's in the term "anion," suggesting its negative charge.

Conversely, cations are positively charged ions that occur when an atom loses one or more electrons. This loss results in a greater number of protons than electrons, leading to a net positive charge. Using the hydrogen atom again, if it loses its single electron, it will have only one proton remaining, thus becoming a cation. The 't' in "cation" can be associated with the positive charge, as it resembles a plus sign.

In summary, the distinction between anions and cations is crucial: anions are negatively charged due to the gain of electrons, while cations are positively charged due to the loss of electrons. The term "ion" encompasses both types, and understanding this difference is essential for exploring ionic bonding in greater detail.

Ionic bonds are formed through electrical attractions between oppositely charged ions, specifically cations and anions. Unlike covalent bonds, which involve the sharing of electrons, ionic bonds are characterized by a complete transfer of electrons from one atom to another. This transfer allows both atoms to achieve full valence shells, which is crucial for their stability.

For example, in the formation of sodium chloride (NaCl), sodium (Na) and chloride (Cl) atoms interact. Chloride is significantly more electronegative than sodium, meaning it has a stronger tendency to attract electrons. As a result, chloride effectively "steals" an electron from sodium. Sodium has one electron in its valence shell, and upon losing this electron, it achieves a full valence shell, while chloride, which was missing one electron, also completes its valence shell.

After the electron transfer, sodium becomes a positively charged ion (Na⁺) because it has lost a negatively charged electron, while chloride becomes a negatively charged ion (Cl^-) due to the gain of that electron. The attraction between these oppositely charged ions leads to the formation of an ionic bond, resulting in the creation of the sodium chloride molecule, which is commonly known as table salt.

In summary, ionic bonds are essential for the formation of stable compounds like sodium chloride, demonstrating how the transfer of electrons can lead to the creation of charged ions and the resulting ionic bonds that hold them together.