Question

Which of the following statements are true regarding a covalent bond between nitrogen and oxygen atoms in a nitric oxide, NO, molecule? (a) Valence electrons are shared between nitrogen and oxygen atoms. (b) Bonding electrons are found only between the bonded atoms. (c) The bond length is greater than the sum of the two atomic radii. (d) Energy is required to break a covalent bond.

Short answer

Statements (a), (b), and (d) are true; (c) is false.

Step-by-step solution

Understanding Covalent Bonds

In a covalent bond, atoms share valence electrons to achieve a full outer shell, allowing them to attain a more stable electronic configuration.

Evaluating Statement (a)

Statement (a) is "Valence electrons are shared between nitrogen and oxygen atoms." In a covalent bond, such as in NO, nitrogen and oxygen atoms will share valence electrons to form the bond, making this statement true.

Evaluating Statement (b)

Statement (b) is "Bonding electrons are found only between the bonded atoms." Covalent bonds involve electrons that are shared in a molecular orbital located between the two atoms, so bonding electrons are typically found between the bonded atoms. Thus, this statement is true.

Evaluating Statement (c)

Statement (c) is "The bond length is greater than the sum of the two atomic radii." Generally, the bond length is less than the sum of atomic radii because atoms come closer than their atomic radii to form a bond. Thus, this statement is false.

Evaluating Statement (d)

Statement (d) is "Energy is required to break a covalent bond." Breaking covalent bonds requires energy to overcome the attraction between the shared electrons and the nuclei, so this statement is true.

Key concepts

Valence Electrons

Valence electrons play a key role in the formation of covalent bonds. They are the outermost electrons found in an atom and are available for bonding. Atoms aim to attain a full outer shell to achieve stable electronic structures seen in noble gases. In the case of nitric oxide (NO), nitrogen and oxygen share their valence electrons to form a stable molecule.

When atoms share valence electrons, they form covalent bonds, which help complete their outer electron shell. For nitrogen and oxygen, this sharing results in a partial sharing of eight electrons between them. This sharing brings both atoms closer to achieving an electron configuration akin to that of more stable atoms. Understanding valence electrons is crucial to grasp how covalent bonding stabilizes molecules like NO.

Bond Length

The bond length in a molecule is the average distance between the nuclei of two bonded atoms. For nitric oxide, the bond length is a specific distance reflecting the optimal balance between attractive and repulsive forces between atoms.

Generally, the bond length in covalent bonds is shorter than the sum of the atomic radii of the two atoms involved. This is because when atoms form bonds, they pull closer to each other than their individual atomic sizes suggest. Thus, in NO, the bond length is actually shorter than the individual radii added together, which allows strong bonding interactions between nitrogen and oxygen.

Bond Energy

Bond energy is the measure of strength of a chemical bond. It indicates how much energy is required to break the bond. In the case of a covalent bond like that in nitric oxide, it represents the energy needed to separate nitrogen and oxygen atoms.

A higher bond energy signifies a stronger bond, suggesting the atoms are held together quite firmly. For molecules with stable covalent bonds, such as NO, significant energy must be supplied to overcome the attraction between the shared electrons and the two nuclei. This is why energy input, often in the form of heat, is required to break a covalent bond.

Nitric Oxide Molecule

The nitric oxide (NO) molecule is a small diatomic molecule consisting of one nitrogen atom and one oxygen atom. It plays important roles in various biological and environmental processes.

In the NO molecule, nitrogen and oxygen are linked by a covalent bond formed through the sharing of valence electrons. This bond involves a straightforward but important interaction between these elements. Moreover, nitric oxide is known for its role as a signaling molecule in biological systems and as a pollutant participating in reactions to form smog in the atmosphere.

Understanding the basic structure and bonding in NO provides insight into its stability and functions across different fields of science.