Properties of Solids Review

What is the bond angle of sp?

180

What is the bond angle of sp2?

120

What is the bond angle of sp3?

109\.5

What is the bond angle of sp3d?

120 between atoms on the x axis, 90 between x axis and y axis molecules

What is the bond angle between sp3d2?

90 between all

Which atoms are electron deficient?

Everything left of Carbon (besides Lithium)

What does VSEPR stand for?

Valence Shell Electron Pair Repulsion

What is VSEPR theory?

All pairs of e- on the valence shell repel as far apart as possible.

What is the EN range of non polar covalent bonds?

0\.0-0.5

What is the EN range of polar covalent bonds?

0\.5-1.7

What is the EN range of ionic bonds?

1\.7-4.0

A molecule will be non-polar if…

It has all non-polar bonds or is symmetrical so dipoles cancel.

A molecule will be polar if…

It has polar bonds AND is non-symmetrical so dipoles do not cancel.

What does intra mean (as in intramolecular)?

Intra=within

What does inter mean (as in intermolecular)?

Inter=between

List the vanderwaal forces

Dip-dip, London dispersion, hydrogen bonding

What are dip-dip bonds?

Bond that occurs between a positive end of one polar molecule and a negative end of another. 1% as strong as covalent.

What are H-bonds?

Occurs between a Hydrogen bonded to a high EN atom and a partially negative atom on another molecule. 10-20x weaker than covalent.

What are London dispersion forces?

A force that exists between non-polar molecules, this increases as molecular mass increases. The weakest force.

Which forces create high m.p, high b.p, high surface tension and high viscosity?

Dip-dip and h-bonding

What is surface tension?

The resistance of a liquid to increase its surface area. Liquids with large intermolecular forces have high surface tension.

What is capillary action?

The ability of a liquid to rise in a narrow tube. Caused by cohesive and adhesive forces.

What is the difference between cohesive and adhesive forces?

Cohesive- intermolecular forces within entities of liquids.

Adhesive- forces between liquid and the container.

Is Ionic bonding stronger or weaker than all intermolecular forces?

Stronger

Properties of Ionic Solids:

1. Hard but brittle
2. Conduct electricity in liquid state or when in solutions
3. High m.p

Define Ionic solids:

Crystal structure of ions held together by strong directional ionic bonds.

What are metallic crystals?

Metals have low ionization energy so they do not form ionic bonds with themselves or with other metals. They hold electrons loosely and share them.

Properties of metallic crystals:

1. Conduct electricity
2. Malleable and ductile
3. High m.p and b.p

Define small molecular crystals:

Crystals of elements or compounds

Properties of small molecular crystals:

1. Low m.p and b.p
2. Not very hard
3. Non-conductors

Why do properties vary between metallic and small molecular crystals?

Because metallic crystals cannot form ionic bonds this causes it to use dip-dip and h-bonding which creates increased m.p and b.p.

Define Covalent network crystals:

Atoms joined by strong directional covalent bonds in a covalent network.

Explain diamond:

Each Carbon is sp3 hybridized to adjacent carbon. It is a large molecule, covalent bonds hold it together no electrons are localized.

Explain graphite:

Each Carbon is bonded to 3 sp3 hybridized carbon. It has a delocalized structure that conducts.

Properties of covalent network crystals:

1. Extremely Hard
2. Brittle
3. Very high m.p and b.p
4. Insoluble
5. Non conductors (except graphite)