Predict the chemical formula of the ionic compound formed between the following pairs of elements: (b) K and S

Key Concepts

Ionic Compounds

Ionic compounds are formed when atoms transfer electrons, resulting in the formation of positively charged cations and negatively charged anions. These oppositely charged ions attract each other, creating a stable ionic bond. The overall charge of the compound must be neutral, meaning the total positive charge must balance the total negative charge.

Valence Electrons

Valence electrons are the outermost electrons of an atom and are crucial in determining how an element will bond with others. For potassium (K), which has one valence electron, it tends to lose that electron to achieve a stable electron configuration. Sulfur (S), with six valence electrons, typically gains two electrons to complete its outer shell, forming an anion.

Chemical Formula Representation

The chemical formula of an ionic compound reflects the ratio of the constituent ions that results in a neutral charge. For potassium and sulfur, potassium forms a K+ ion and sulfur forms an S2- ion. To balance the charges, two potassium ions are needed for every one sulfur ion, leading to the formula K2S.