National League for Nursing (NLN PAX) Practice Exam

When two atoms share a pair of electrons, what type of bond is formed?

1. Electrovalent

2. Covalent

3. Ionic

4. Metallic

The correct answer is: Covalent

When two atoms share a pair of electrons, a covalent bond is formed. This type of bond occurs when atoms have similar electronegativities, which means they have a comparable tendency to attract electrons. By sharing electrons, each atom effectively fills its outermost electron shell, leading to greater stability and forming a strong connection between the atoms. Covalent bonds can vary in strength and character based on how many pairs of electrons are shared; for example, a single bond involves one shared pair, while double bonds involve two shared pairs. In molecular compounds, covalent bonding plays a crucial role in determining the properties and behavior of substances. Other types of bonds exist, such as ionic bonds, where electrons are transferred from one atom to another, leading to the formation of charged ions. Metallic bonds involve a 'sea of electrons' shared among a lattice of metal atoms, contributing to properties such as conductivity and malleability. Electrovalent, a term often used interchangeably with ionic bonds, specifically refers to this transfer of electrons rather than the sharing that defines covalent bonding. Thus, the key aspect here is the sharing of electrons, which is characteristic of covalent bonds.