Ionic Bonding Quiz: Electron Transfer & Compound Formulas

Ionic bonds form when a metal transfers electrons to a nonmetal. Metals lose electrons due to low ionization energy, forming positive cations. Nonmetals gain electrons because of high electronegativity, forming negative anions. The electrostatic attraction between oppositely charged ions creates the ionic bond. This transfer leads to a stable electron configuration resembling noble gases and results in a strong crystal lattice structure.

Nitrogen is a nonmetal with five valence electrons. To achieve a stable octet, it gains three electrons, forming a −3 charged ion. When it gains electrons, it becomes negatively charged, classifying it as an anion. In ionic bonding, nonmetals typically form anions because they attract electrons due to higher electronegativity compared to metals.

Lithium forms a +1 ion by losing one electron, while nitrogen forms a −3 ion by gaining three electrons. To balance charges, three lithium ions are required for every nitrogen ion. This ensures total positive charge equals total negative charge. The resulting neutral compound is lithium nitride with formula Li3N, following ionic charge balancing rules.

Nickel (II) indicates a +2 charge on nickel. Chlorine forms a −1 ion. To achieve charge neutrality, one nickel ion combines with two chloride ions. The total charge becomes +2 and −2, balancing to zero. Because nickel has multiple oxidation states, the Roman numeral specifies charge. Therefore, the correct compound is Nickel (II) Chloride with formula NiCl2.

Boron has a +3 charge and nitrogen has a −3 charge. Since the charges are equal in magnitude but opposite in sign, they balance in a one-to-one ratio. Only one boron atom and one nitrogen atom are required to achieve neutrality. The compound formed is boron nitride with the empirical formula BN.

Mercury (II) carries a +2 charge, while oxygen carries a −2 charge. Since their charges are equal and opposite, they combine in a one-to-one ratio. The Roman numeral II clarifies mercury’s oxidation state. One mercury ion transfers two electrons to one oxygen ion, forming HgO. This balanced ratio ensures electrical neutrality in the compound.

Ionic compounds are brittle because when force shifts the lattice layers, like-charged ions align next to each other. Since like charges repel strongly, the electrostatic repulsion destabilizes the structure. This causes the crystal to fracture rather than bend. Unlike metallic bonding, ionic bonding lacks mobile electrons to maintain attraction after displacement, resulting in brittleness.

Calcium forms a +2 ion, while chlorine forms a −1 ion. To balance the charges, two chloride ions are needed for every calcium ion. This creates a neutral compound where total positive charge equals total negative charge. The correct formula is CaCl2, following standard ionic charge balancing and writing conventions.

Ionic compounds have high melting points because strong electrostatic attractions hold oppositely charged ions together in a rigid lattice. Breaking these forces requires significant energy input. Unlike covalent molecules with weaker intermolecular forces, ionic solids consist of extensive ionic networks. This strong bonding results in elevated melting temperatures compared to most molecular compounds.

In molten ionic compounds, heat provides enough energy to break lattice structure, freeing ions to move. Once mobile, these charged particles can carry electric current. In solid form, ions are fixed and cannot move, preventing conductivity. Therefore, ionic compounds conduct electricity only when molten or dissolved, not when solid.