Properties of covalent substances | Starter Quiz | Oak National Academy

What type of bond typically forms between two non-metal atoms?

• Ionic bond

• Covalent bond

• Metallic bond

Answer explanation

A covalent bond typically forms between two non-metal atoms where they share pairs of electrons. Ionic bonds typically form between metals and non-metals, and metallic bonds occur between metal atoms.

How many pairs of electrons are shared between two carbon atoms in ethene (shown in the diagram)?

• 1

• 2

• 3

• 4

• 8

Answer explanation

A double bond represents the sharing of two pairs of electrons between atoms. Here, a total of 4 electrons are shared between the carbon atoms.

Which of the following is an example of a molecule formed by covalent bonding?

• NaCl

• MgO

• CO₂

• Fe

Answer explanation

CO₂ (carbon dioxide) is a molecule formed by covalent bonding between carbon and oxygen atoms. NaCl and MgO are ionic compounds, and Fe is a metallic element.

How many electrons are shared in a single covalent bond?

Answer explanation

Two electrons are shared in a single covalent bond, with each atom contributing one electron to the bond.

A displayed formula represents a covalent substance, showing ___ to represent shared pairs of electrons between atoms.

Answer explanation

A displayed formula represents a covalent substance, showing lines to represent shared pairs of electrons between atoms. It provides a visual model of the molecule's structure.

Arrange the following molecules by the number of covalent bonds each has, from least to most:

• CH₄

• H₂

• O₂

• N₂

Answer explanation

The correct order is: H₂, O₂, N₂, CH₄. H₂ has one single bond, O₂ has a double bond, and N₂ has a triple bond. CH₄ is made up of 4 C-H bonds.