Molecular Models

Question 0

Hybridization

Answer 0

A process by which electrons mix traits of different atomic orbitals to create bonding orbitals. The hybridization model helps explain the difference in bond strength between Sigma and pi bonds and correctly predicts the geometry of molecules.

Question 1

Lewis structures

Answer 1

Model the valence electrons that are involved in covalent bonding.

The group number on the periodic table gives the number of valence electrons available for bonding.

Normally, the “octet rule “must be satisfied to combine other atoms with a central atom – that is, the combination of the central atom’s valence electrons and the electrons from other atoms bonded to the central atom should equal eight to create a stable bluest structure.

Resonance structures are an attempt to model delocalized electrons. For example, to allow the octet of sulfur in the sulfur dioxide molecule to be satisfied, it would show a double bond to one oxygen and not the other. However, the bonds to both oxygen atoms are equal, and demonstrate a bond length and strength somewhere between a single and a double bond.

Lewis structures are limited because they do not adequately depict delocalized electrons (except through resonance structures), show the difference between Sigma and pi bonds, or explain the concept of expanded octets.

Question 2

VSEPR (valence shell electron-pair repulsion)

Answer 2

VSEPR dictates that electron pairs will repel each another, thus creating a molecular geometry in which each electron pair is as far as possible from every other electron pair. Unbonded pairs are slightly more repellent than other pairs.

Question 3

Expanded octet

Answer 3

Expanded octets are created when highly electronegative atoms bond to large central atoms and there is space to allow either five or six electron pairs around the central atom.

Question 4

Isomers

Answer 4

Isomers are molecules that have the same formula but different structure- or arrangement of the atoms. Two isomers will have different physical and chemical properties, which will depend on how the atoms are arranged and the intermolecular forces that are created as a result.