Lewis structure Quiz: Test Your Knowledge

Carbon dioxide consists of a central carbon atom sharing four electrons with each of two oxygen atoms. This arrangement creates two double bonds, allowing every atom to satisfy the octet rule by sharing enough electrons for stability. In this linear configuration, the molecule remains nonpolar since the oxygen atoms pull electrons equally from opposite directions. This fundamental structure explains why carbon dioxide is a gas at room temperature.

Xenon is a noble gas that typically remains unreactive, but it forms compounds like xenon tetrafluoride under specific conditions. In its Lewis structure, the central xenon atom possesses eight valence electrons. After sharing four electrons to create single covalent bonds with four fluorine atoms, the remaining four electrons form two lone pairs, resulting in a square planar molecular geometry.

Phosphorus belongs to group fifteen and contributes five valence electrons to the molecule. Each of the five chlorine atoms from group seventeen provides seven valence electrons, totaling thirty-five. Combining these values gives forty total electrons. Phosphorus pentachloride is a notable example of an expanded octet, meaning the central atom holds more than eight electrons to accommodate all five chemical bonds during synthesis.

Hydrogen cyanide consists of a carbon atom bonded to both hydrogen and nitrogen. Within its Lewis structure, carbon and nitrogen share three pairs of electrons to create a triple bond. This specific arrangement allows both atoms to satisfy the octet rule, achieving a stable electronic state. These six shared electrons result in a short, strong chemical bond that determines the linear geometry of the entire molecule.

Formal charge is a chemical concept used to track valence electrons within molecules. It is calculated by comparing the electrons assigned to an atom in a Lewis structure against its neutral state. Carbonate ions contain one oxygen with a double bond and two others with single bonds. These single-bonded atoms retain seven electrons, resulting in a formal charge of negative one for each oxygen.

In the nitrogen trifluoride molecule, the central nitrogen atom shares three electrons with fluorine atoms to form covalent bonds. This leaves one lone pair on the nitrogen. Each of the three fluorine atoms possesses three lone pairs to complete their valence shells. Summing these results in ten total lone pairs. This compound is a colorless gas frequently utilized in semiconductor manufacturing for plasma etching.

The phosphate ion consists of a central phosphorus atom surrounded by four oxygen atoms. To satisfy the octet rule, phosphorus forms four single bonds. Since phosphorus naturally possesses five valence electrons, its formal charge is calculated by subtracting its four assigned bonding electrons from its initial count. This results in a charge of plus one, while each oxygen atom maintains a negative charge to balance the ion.

In the carbon monoxide molecule, carbon and oxygen are connected by a triple bond. To satisfy its octet, oxygen shares six electrons and keeps two as a lone pair. Formal charge is determined by subtracting unshared electrons and half of the shared electrons from the valence total. Because oxygen has six valence electrons, subtracting five results in a formal charge of plus one.

The nitrite ion contains a central nitrogen atom covalently bonded to two oxygen atoms. Formal charge is determined by comparing an atom’s valence electrons to its actual bonding environment. For nitrogen, which has five valence electrons, the stable arrangement involves one double bond, one single bond, and a lone pair. These assignments sum to five, resulting in a formal charge of zero on the central nitrogen.

Boron has three valence electrons and forms three single bonds with fluorine atoms. In the boron trifluoride molecule, the central boron atom utilizes all its available electrons for bonding, leaving zero lone pairs. This results in an electron deficient center with only six valence electrons, making boron an exception to the octet rule. Consequently, BF3 acts as a Lewis acid by accepting electron pairs.

The hydronium ion consists of three hydrogen atoms covalently bonded to a single central oxygen atom. In its neutral state, oxygen possesses six valence electrons. When it forms three bonds with hydrogen and loses one electron to create a positive charge, it retains two unshared electrons. This pair of electrons constitutes the lone pair found on the oxygen atom in this specific molecular structure.

Nitrogen typically has five valence electrons. When it forms an ammonium ion, it shares four electrons with four hydrogen atoms to create covalent bonds. The positive charge represents the loss of one electron, meaning nitrogen effectively uses all its available valence electrons for bonding. This configuration follows the octet rule, resulting in a tetrahedral geometry where the central atom lacks any lone pairs.

Sulfur hexafluoride is a hypervalent molecule where the central sulfur atom expands its valence shell to accommodate more than eight electrons. In this specific arrangement, sulfur forms six single covalent bonds with surrounding fluorine atoms. Since each covalent bond consists of two shared electrons, the central sulfur atom holds a total of twelve bonding electrons, resulting in a stable octahedral molecular geometry commonly studied in chemistry.

Chlorine trifluoride consists of a central chlorine atom bonded to three fluorine atoms. Chlorine has seven valence electrons, and each bond uses one of those electrons. This leaves four remaining valence electrons on the chlorine atom, which organize into two lone pairs. These extra electrons cause the molecule to adopt an expanded octet and distinct molecular geometry to minimize electrostatic repulsion between different electron groups.

Cyanide is a potent toxin that inhibits cellular respiration in organisms. In its chemical structure, carbon and nitrogen atoms are joined by a triple bond, with both atoms having one lone pair. Carbon naturally has four valence electrons, but in this arrangement, it possesses five electrons. This imbalance results in the carbon atom being assigned a formal charge of negative one.

Carbon tetrachloride is a symmetric molecule where one carbon atom bonds to four chlorine atoms using single covalent bonds. Carbon contributes four valence electrons, while each chlorine atom provides seven. After forming these four bonds, the carbon atom has no remaining electrons. However, each chlorine atom retains six unshared electrons, arranged as three lone pairs. Multiplying these three pairs by four atoms results in twelve total lone pairs.

Sulfur dioxide consists of one sulfur atom double-bonded to two oxygen atoms. Sulfur possesses six valence electrons and uses four of these to form chemical bonds. The remaining two electrons reside on the sulfur atom as a single lone pair. This specific electronic arrangement minimizes the formal charge of the molecule while creating a bent molecular geometry due to electron repulsion between the pairs.

The carbonate ion contains a central carbon atom bonded to three oxygen atoms. Resonance occurs because a single double bond can be placed between the carbon and any of the three oxygen atoms. This results in three equivalent Lewis structures. In nature, the electrons are delocalized, meaning they are shared equally. This creates bond lengths that are identical and intermediate between single and double bonds.

Xenon difluoride consists of a central xenon atom bonded to two fluorine atoms. As a noble gas, xenon possesses eight valence electrons. After forming two single covalent bonds, the atom retains six non-bonding electrons. These remaining electrons group into three lone pairs, which distribute symmetrically around the center. This specific electronic arrangement results in a linear molecular shape according to standard chemical bonding theories.

The nitrate ion consists of one nitrogen atom and three oxygen atoms. Nitrogen belongs to the fifteenth group of the periodic table, providing five valence electrons. Oxygen resides in the sixteenth group, contributing six electrons each. Since the ion carries a negative charge, an additional electron is added to the count. The mathematical sum of five plus eighteen plus one equals exactly 24 total valence electrons.

Ozone is a triatomic molecule consisting of three oxygen atoms. In its Lewis structure, the central oxygen atom forms a double bond with one neighbor and a single bond with the other, while retaining one lone pair of electrons. Calculating formal charge involves subtracting nonbonding electrons and half of bonding electrons from the six valence electrons, resulting in a positive charge of one for that central atom.