Question

Draw Lewis structures for chlorine nitrate \(\left(\mathrm{ClONO}_{2}\right)\) and chlorine monoxide \((\mathrm{ClO})\).

Short answer

For ClONO2, N is in the center with Cl, double-bonded O, and single-bonded O. For ClO, Cl and O are single-bonded.

Step-by-step solution

Determine Total Valence Electrons for ClONO2

To draw the Lewis structure for chlorine nitrate (ClONO2), first determine the total number of valence electrons. Chlorine (Cl) has 7 valence electrons, each oxygen (O) has 6, and nitrogen (N) has 5. Adding these up gives: \(7 + 6 \times 2 + 5 = 24\) electrons.

Arrange Atoms and Connect with Single Bonds

Place the least electronegative atom, nitrogen (N), at the center. Attach Cl, one O directly to N, and one O next to the remaining O to make NO2 group. Draw single bonds connecting them: N bonded to Cl and each O. Initial structure: Cl-N-O-O.

Distribute Remaining Electrons as Lone Pairs

Subtract the electrons used in bonds (4 bonds x 2 electrons = 8 electrons) from the total: 24 - 8 = 16. Distribute these 16 electrons as lone pairs to satisfy the octet rule for each atom where possible, starting with terminal oxygens.

Satisfy Octet Rule Using Double Bonds if Necessary

If any atom does not have a full octet (except Cl, N, or O), move lone pair electrons to form double or triple bonds. For example, form a double bond between N and one of the Os. Final structure should have Cl with three lone pairs and doubly bonded nitrogen to one oxygen, with single bonds to the other oxygen.

Determine Total Valence Electrons for ClO

For chlorine monoxide (ClO), calculate the total valence electrons. Chlorine has 7, and oxygen has 6. Therefore, ClO has \(7 + 6 = 13\) valence electrons.

Draw Skeleton Structure for ClO

Draw a single bond connecting Cl and O, using 2 of the 13 valence electrons, remaining electrons: 11.

Distribute Electrons to Complete Octet

Assign the remaining 11 electrons as lone pairs to satisfy the octet rule around each atom: Oxygen gets 6 more electrons (3 pairs) and Chlorine gets the remaining 5 electrons as lone pairs.

Key concepts

Valence Electrons

Valence electrons are the outermost electrons of an atom and play a crucial role in forming chemical bonds. These electrons are found in the highest energy level (shell) of an atom. For example, chlorine (Cl) has 7 valence electrons as it is in Group 17 of the periodic table. Oxygen (O), with 6 valence electrons, belongs to Group 16, and nitrogen (N), with 5 valence electrons, falls in Group 15.

Understanding valence electrons helps us predict how elements interact with one another. These electrons determine an element's chemical properties and its ability to bond with other atoms. In a Lewis structure, valence electrons are represented as dots around the element symbols. They are used to form either bonding or non-bonding pairs, influencing the stability and structure of the molecule.

• Valence electrons determine reactivity and bonding.
• Found in the outermost shell.
• Represented as dots in Lewis structures.

This understanding is critical for drawing Lewis structures, as seen in the molecules chlorine nitrate (ClONO2) and chlorine monoxide (ClO).

Octet Rule

The octet rule is a guiding principle in chemistry, stating that atoms seek to have eight electrons in their valence shell to attain a noble gas-like electron configuration. However, there are some exceptions to this rule, such as hydrogen (H), which only requires two electrons to be stable.

In drawing Lewis structures, the octet rule helps us determine how atoms share or transfer electrons. It's often necessary to use lone pairs of electrons to form double or even triple bonds to achieve a full octet. For instance, in the structure of chlorine nitrate, the nitrogen atom forms a double bond with one of the oxygen atoms to satisfy its octet requirement, involving electron redistribution among atoms.

When working with molecules, ensure each atom follows the octet rule when possible:

• Aim for 8 electrons in the outer shell.
• Utilize shared (bonding) or lone (non-bonding) pairs.
• Form double/triple bonds to complete octets.

Note that some molecules like Cl, N, and O may not strictly follow the full octet due to their atomic size or available electrons, but they strive to get as close as possible while maintaining stability.

Chlorine Nitrate

Chlorine nitrate (ClONO2) is a compound derived from chlorine and nitrogen oxides. Drawing its Lewis structure involves several steps to distribute valence electrons correctly.

Initially, calculate the total number of valence electrons available, which is 24 for ClONO2, considering each atom's contribution. Nitrogen, less electronegative than oxygen, is placed centrally and bonds to chlorine and oxygen atoms.

Distributing electrons involves first using pairs to form basic bonds, ensuring each atom's octet is satisfied when feasible. For nitrogen, double bonds or lone pairs can be adjusted to achieve a preferable distribution. The completed structure should accurately reflect:

• 7 electrons from chlorine.
• 5 electrons from nitrogen.
• 6 electrons from each oxygen.

Understanding the concept helps in achieving a stable molecule where all atoms are ideally surrounded by shared and lone electrons that satisfy the octet rule.

Chlorine Monoxide

Chlorine monoxide (ClO) involves a simpler structure than that of chlorine nitrate, given it consists of only two atoms: chlorine and oxygen.

The combined valence electron count is 13 for ClO, derived from 7 electrons from chlorine and 6 from oxygen. In creating the Lewis structure, a single bond between Cl and O uses two electrons, while the remaining 11 distribute between them as lone pairs.

Here, both atoms strive for an octet. Oxygen typically needs three pairs of non-bonding electrons after the Cl-O bond. Chlorine will pick up the remaining, satisfying its shell with 7 lone electrons. This configuration stands as follows:

• Cl-O bond using 2 electrons.
• Oxygen completes its octet with 3 pairs of lone electrons.
• Chlorine holds the remaining lone electrons to maximize stability.

This simpler structure still underscores the need to balance and allocate electrons such that each atom's electron desire is reasonably satisfied, maintaining molecule integrity.