Chemistry 1201: Ch. 9 - Molecular Geometry and Bonding Theories

Electrons in bonds and lone pairs repel each other and seek to be ... as possible to minimize these repulsions

As far apart

If there are 2 Electron Domains, then the Electron-Domain Geometry will be ... and the Predicted Bond Angles will be ...

Linear; 180°

If there are 3 Electron Domains, then the Electron-Domain Geometry will be ... and the Predicted Bond Angles will be ...

Trigonal Planar; 120°

If there are 4 Electron Domains, then the Electron-Domain Geometry will be ... and the Predicted Bond Angles will be ...

Tetrahedral; 109.5°

If there are 5 Electron Domains, then the Electron-Domain Geometry will be ... and the Predicted Bond Angles will be ...

Trigonal bipyramidal; 120° or 90°/180°

If there are 6 Electron Domains, then the Electron-Domain Geometry will be ... and the Predicted Bond Angles will be ...

Octahedral; 90°/180°

Trigonal bipyramidal and Octahedral electron geometries are possible only when there is ...

An expanded octet of electrons on the central atom

Will a double bond in an atom cause different angles in its trigonal planar shape compared to an atom with only single bonds? If so, then what will those angle be?

Yes;
Angles near the double bonded atom x>120°
Angle near the single bonded atoms x<120°

True or False: The space (angle) needed by a triple bond is less than a single bond.

False; Greater

Molecular shape will be different if there are any ... in the molecule

lone pairs

Bond angles are ... (greater or less) because of lone pair repulsions

less

Resonance means that all bonds will be ...

Equal

The presence of one lone pair in the central atom of a molecule with an electron-domain geometry that is trigonal planar will have a molecular geometry that is ...

Bent

There are 5 Electron-Domains, 3 Bonding Domains and 2 Non-Bonding Domains, the Molecular Geometry will be ...

T-shaped

There are 6 Electron-Domains, 5 Bonding Domains and 1 Non-Bonding Domains, the Molecular Geometry will be ...

Square Pyramidal

Breaking of ideal electron pair geometry due to the presence of nonbinding electron pairs or multiple bonds may give rise to molecular ...

Polarity

2 Conditions necessary for a molecule to be polar ...

1) Typically, bonds within the molecule need to be polar
2) Molecules must have lower symmetry than the ideal electron domain geometry

One must know the ... before making calls about the molecular polarity

Molecular Shape/Geometry

Molecular Polarity is a ... of bond polarites

Vector Sum

In some highly symmetrical molecules, bond dipoles ... , and the molecule is non-polar

Cancel

Why do we care if a molecular is polar or not?

1) Polar molecules strongly interact with each other via dipole-dipole interactions.
2) "Likes dissolves like" (Polar & Polar; Non-Polar & Non-Polar)

True or False: Each pair of bonded atoms has an optimal bond distance which corresponds to the minimum potential energy and strongest attraction between atoms.

True!

A σ (Sigma) Bond is when ...

The area of overlap is symmetrically distributed about the bond axis (May require hybrid orbitals).
These are single bonds and one of the bonds in a double or triple bond!

A π (Pi) Bond is when ...

The overlap region is below and above the bond axis.
Seen in Double Bonds and Triple Bonds!

Valence Bond Theory

In order to form a bond between two atoms:
1) Orbitals in atoms must overlap
2) 2 Electrons (↑ and ↓) must be placed in the area of overlap

Hybridization is ...

Mixing of atomic orbitals on an atom to obtain a set of hybrid orbitals with the same shape and energy, but with different orientations in space which provides for the best overlap with orbitals on other atoms

What needs a hybrid orbital?

1) A σ component of any bond
2) A lone (Non-binding) electron pair
3) A single electron in a radical

True or False: A π bond does not require hybrid orbitals and is present only in multiple bonds in addition to the σ bond

True

The number of hybrid orbitals needed = ...

The number of atomic orbitals we have to mix in

An atomic orbital set with sp^2 will have a geometry of a ...

Trigonal Planar

An atomic orbital set with sp^3 d will have a geometry of a ...

Trigonal bipyramidal

An atomic orbital set with sp^3 d^2 will have a geometry of a ...

Octahedral

True or False: Molecular Shape is not primarily determined by the bonds and angles between them.

False; It is

Is SO3 polar or nonpolar?

Nonpolar

Is SO2 polar or nonpolar?

Polar

Is PCl3 polar or nonpolar?

Polar

Is PCl5 polar or nonpolar?

Nonpolar

Is CH2O polar or nonpolar?

Polar

Is SeF6 polar or nonpolar?

Nonpolar

Is OF2 polar or nonpolar?

Polar

Is SCl4 polar or nonpolar?

Polar

Is CF2Cl2 polar or nonpolar?

Polar

Is CCl4 polar or nonpolar?

Nonpolar

Is PH3 polar or nonpolar?

Polar