The Solid State

Question 1

The stronger the intermolecular forces, the ___________ movement of the particles

Answer 1

Slower

Question 2

What are the properties of amorphous solids?

Answer 2

• random arrangement of particles
• particles have no orderly structure
• macroscopic structures lack well defined faces and shapes
• many are mixtures of molecules that do not stack up well together
• glass and rubber are examples

Question 3

What are the properties of Crystalline Solids?

Answer 3

• atoms, ions, or molecules are arranged in an orderly fashion that follows a pattern of repetition in three dimensions
• macroscopic structures usually have flat surfaces that make definite angles to one another
• ionic solids and quarts are examples

Question 4

Segments in crystalline solids that repeat in three dimensions

Answer 4

Unit cells

Question 5

In liquids particles go thorough ____________ meaning they move around

Answer 5

Translation

Question 6

The corners of the cubes

Answer 6

Lattice points

Question 7

This unit cell contains:
8 corners x 1/8 of an atom
= 1 atom/unit cell

Answer 7

Simple cubic

Question 8

This unit cell contains:
8 corners x 1/8 of an atom + 1 central
=2 atoms/unit cell

Answer 8

Body centered cubic

Question 9

This unit cell contains:
8 corners x 1/8 of an atom + 6 faces x 1/2 of an atom
=4 atoms/unit cell

Answer 9

Face centered cube

Question 10

What are the properties of molecular solids?

Answer 10

• consists of nonmetals, diatomic elements, or compounds composed of two or more nonmetals
• normally do not conduct electricity
• covalently bonded units are held together by weak intermolecular forces
• soft
• have low melting points

Question 11

Why do molecular solids normally not conduct electricity

Answer 11

Electrons are held within the covalent bonds of each molecule

Question 12

What is an example of a molecular solid?

Answer 12

I2

Question 13

___________ fats have stronger dispersion forces, and are solid at room temperature

Answer 13

Unsaturated

Question 14

Why do unsaturated fats have weaker dispersion forces?

Answer 14

A double bond bends the carbon, causing the molecule to be sp2 hybridized, therefore being trigonal planar

Question 15

What is an example of a molecular solid?

Answer 15

Wax

Question 16

One or two nonmetals held together by networks of covalent bonds instead of intermolecular forces

Answer 16

Covalent network solids

Question 17

What are the properties of a covalent network solid?

Answer 17

• very hard

- very high melting points

Question 18

Why are covalent network solids normally very hard?

Answer 18

-atoms are covalently bonded with fixed bond angles

Question 19

In graphite, each carbons forms three _____ hybrid orbitals that bond with three other carbon atoms

Answer 19

Sp2

Question 20

Graphite and diamond are __________ of each other

Answer 20

Allotropes

Question 21

Why can sheets of graphite slide over each other so easily?

Answer 21

Weak pi bonds and london dispersion forces

Question 22

Why does graphite have a high melting point?

Answer 22

The covalent bonds between carbon in each later are relatively strong

Question 23

In diamond, many carbon atoms bond together with _______ hybrid orbitals

Answer 23

Sp3

Question 24

What is the molecular geometry of diamond?

Answer 24

Tetrahedral

Question 25

In diamonds each carbon makes a single covalent bond with ___ other carbon atoms

Answer 25

4

Question 26

Other common covalent network solids include _________ and __________

Answer 26

SiO2 and Si

Question 27

Si is a ______________

Answer 27

Semiconductor

Question 28

Why is bonding in metallic solids not covalent?

Answer 28

Not enough electrons to fill octets

Question 29

How does bonding in metallic solids work?

Answer 29

Attractions between nuclei and delocalized valence electrons move throughout the structure

Question 30

Bond strength in metallic solids __________ as the number of bonding electrons increases

Answer 30

Increases

Question 31

Why so metals bend, not break when hit with a hammer?

Answer 31

There are no directional bonds

Question 32

Describe the electron sea model in metallic bonding

Answer 32

Nuclei and inner shells are stationary, while valence electrons are free to move throughout the solid

Question 33

What are properties of metallic solids?

Answer 33

- conduct electricity - conduct heat - malleable and ductile - lack directional bonds

Question 34

Why do saturated fats have stronger London dispersion forces?

Answer 34

It's linear shape is good for stacking, meaning there are many points of contact between molecules

Question 35

Why are diamonds so hard?

Answer 35

- Diamonds are one massive molecule held together by covalent bonds - the sp3 hybridization allows for a tetrahedral structure which is very strong