Covalent bonds typically form between two non-metal atoms.
What happens to electrons in a covalent bond?
Electrons are shared between atoms in a covalent bond.
What is a single covalent bond?
A single covalent bond is formed when one pair of electrons is shared between two atoms.
What is a double covalent bond?
A double covalent bond is formed when two pairs of electrons are shared between two atoms.
What is a triple covalent bond?
A triple covalent bond is formed when three pairs of electrons are shared between two atoms.
Give two examples of molecules with single covalent bonds.
Hydrogen (H₂) and water (H₂O) are two examples of molecules with single covalent bonds.
Give an example of a molecule with a double covalent bond.
Oxygen (O₂) is an example of a molecule with a double covalent bond.
Give an example of a molecule with a triple covalent bond.
Nitrogen (N₂) is an example of a molecule with a triple covalent bond.
What force holds atoms together in a covalent bond?
Shared electron pairs and the attraction between the positive nuclei and negative electrons.
What are Van der Waals forces?
Weak intermolecular forces between covalent molecules.
Are covalent compounds generally good conductors of electricity?
No, covalent compounds are generally poor conductors of electricity.
What is the typical solubility of covalent compounds in water?
Many covalent compounds are insoluble in water.
Are covalent compounds soluble in organic solvents?
Many covalent compounds are soluble in organic solvents.
How are covalent bonds represented in Lewis structures?
Covalent bonds are represented by shared pairs of electrons, often shown as dots, crosses, or a line between the atoms.
What is the typical state of covalent compounds at room temperature?
Covalent compounds can be gases, liquids, or solids, some are volatile.
How does covalent bonding help atoms achieve stable electron configurations?
Atoms share electrons to fill their outer shells, achieving a stable duplet or octet.
Name a covalent compound that is a gas at room temperature.
Hydrogen (H₂) or Carbon dioxide (CO₂) are gases at room temperature.
Name a covalent compound that is a liquid at room temperature.
Water (H₂O) is a liquid at room temperature.
What is a giant molecular structure?
A structure with many atoms bonded to each other by covalent bonds in a continuous network.
Name a covalent compound that is a solid at room temperature.
Diamond or graphite are solids at room temperature.
Explanation Questions
Explain why covalent bonds form between non-metal atoms.
Covalent bonds form between non-metal atoms because non-metals have high electronegativity and are more likely to share electrons to achieve a stable electron configuration, rather than transferring them completely as in ionic bonding.
Describe how sharing electrons leads to the formation of a covalent bond.
In a covalent bond, atoms share valence electrons so that each atom can achieve a stable electron configuration. The positively charged nuclei of the atoms are attracted to the shared negatively charged electrons between them, holding the atoms together to form a covalent bond.
How does the number of shared electron pairs affect the strength of a covalent bond?
The greater the number of shared electron pairs (single, double, or triple bonds), the stronger the covalent bond because more electrons are involved in the attraction to the nuclei and this increases the overall bond strength.
Why do covalent compounds generally have low melting and boiling points compared to ionic compounds?
Covalent compounds have weaker intermolecular forces (Van der Waals forces) between molecules. These forces are easier to overcome than the strong electrostatic forces holding ions together in ionic compounds, resulting in lower melting and boiling points.
Explain why covalent compounds are generally poor conductors of electricity.
Covalent compounds are generally poor conductors of electricity because they do not have mobile charged particles (ions) that can carry an electrical current, instead the electrons are localized in the covalent bonds between atoms.
Describe the role of Lewis structures in representing covalent bonds.
Lewis structures use dots or crosses to represent valence electrons, showing how electrons are shared between atoms in a covalent bond. The Lewis structures help visualise the arrangement of electron pairs and the formation of single, double, or triple bonds.
How does the electronegativity difference between atoms affect the covalent bond?
If two atoms have similar electronegativity, they will share electrons equally forming a non-polar covalent bond. If they have different electronegativities, the electrons will be shared unequally creating a polar covalent bond and potentially a molecule with partial positive and negative charges.
Explain the difference between simple molecules and giant molecular structures in covalent compounds.
Simple covalent molecules consist of a fixed, small number of atoms, linked together by covalent bonds, such as water (H₂O) or methane (CH₄). Giant molecular structures, such as diamond and graphite, have a continuous network of covalently bonded atoms extending throughout the structure.
Using water (H₂O) as an example, explain how covalent bonds are formed.
In a water molecule, each hydrogen atom shares its single valence electron with an oxygen atom which has 6 valence electrons. The oxygen atom shares one electron with each of the hydrogen atoms, resulting in both hydrogen atoms having 2 valence electrons in their outer shell and the oxygen atom having 8 valence electrons in its outer shell.
How does the sharing of electrons help atoms achieve stability in covalent compounds?
By sharing electrons, atoms can achieve a full outer shell of electrons, either a duplet or an octet, which is the most stable electron configuration. Sharing electrons avoids the need to completely gain or lose electrons, resulting in stability within the covalent bond.