Chapter 2

Question 1

What are the four properties that are determined my an atom’s electronic structure/configuration?

Answer 1

Chemical, electrical, thermal, optical

Question 2

What are two wave-like characteristics?

Answer 2

1. Electron position in terms of probability density
2. Shape, size, orientation or probability density determined by quantum numbers

Question 3

What happens to a metal atom during the ionization process? A nonmetal?

Answer 3

metal atom: donates electrons

nonmetal atom: accepts electrons

Question 4

What is required for ionic bonding?

Answer 4

• positive and negative ions
• electron transfer
• ## large difference in electronegativity (X)

Question 5

What are the different parts of the potential energy chart for ionic bonding?

Answer 5

• The net energy is repulsive and very rapidly goes to be attractive, then the net energy slowly gets less attractive as r increases

Question 6

What difference in electronegativity is required for covalent bonding? Why?

Answer 6

Similar electronegativities to share electrons

Question 7

What kinds of electrons are involved in covalent bonding?

Answer 7

Valence electrons– normally s and p orbitals are involved

Question 8

What kind of hybrid orbitals can carbon form?

Answer 8

sp^3

Question 9

In CH4, what kinds of orbitals are electrons shared in?

Answer 9

sp^3

Question 10

How do electrons act in metallic bonding?

Answer 10

electrons delocalized to form electron clouds

Question 11

What is the most common mixed bonding type?

Answer 11

Covalent-ionic mixed bonding

Question 12

Where does secondary bonding come from?

Answer 12

Attractive forces between dipoles

Question 13

What are the two different types of dipoles?

Answer 13

Fluctuating dipoles and permanent dipoles

Question 14

What are examples of secondary bonding? (3)

Answer 14

1. Liquid H2
2. Liquid HCl
3. polymer

Question 15

How does bond length relate to melting temperature?

Answer 15

it has the largest bond length at the unstretched radius length and then it slowly gets closer to the axis

Question 16

How does bond energy relate to the coefficient of thermal expansion?

Answer 16

the small bond energy, the larger coefficient of thermal expansion

Question 17

What kind of bonding do ceramics have?

Answer 17

Ionic and covalent bonding

Question 18

What kind of bonding do metals have?

Answer 18

metallic bonding

Question 19

What kind of bonding do polymers have?

Answer 19

covalent and secondary

Question 20

What are the properties of ceramic’s bonding energy?

Answer 20

high Tm- melting
large E- bonding E
small αl- coeff. of thermal expansion

Question 21

What are the properties of metals’ bonding energy?

Answer 21

moderate Tm - melting
moderate E - bonding E
moderate αl- coeff. of thermal expansion

Question 22

What are the properties of polymers’ bonding energy?

Answer 22

low Tm- melting
small E- bonding E
large αl- coeff. of thermal expansion

** the secondary bonding is responsible for most of the physical properties

Question 23

What does the percent ionic character of a covalent-ionic mixed bond between two elements depend on?

Answer 23

Electronegativities

Question 24

What kind of bonding do molecular solids have?

Answer 24

ver de waals

Question 25

What kind of bonding do semi-metals have?

Answer 25

mixed covalent-metallic

Question 26

what kind of bonding do intermetallic have?

Answer 26

mixed metallic-ionic

Question 27

What’s an example of bonding affecting a material’s properties?

Answer 27

Diamond is a poor conductor or electricity but graphite is a good conductor

Question 28

When some elements covalently bond, what kind of bonds do they form? For C, Si, and Ge

Answer 28

They from sp hybrid orbitals

Question 29

What are two typical properties of nonmetals?

Answer 29

Electrical and thermal insulators

Question 30

Do materials with high bonding energies typically have high or low melting temperature?

Answer 30

high melting temperatures

Question 31

Why are covalently bonded materials generally less dense then ionically or metallically bonded ones?

Answer 31

Covalent bonds are directional in nature whereas metallic and ionic are not; when bonds are directional, the atoms cannot pack together in as dense a manner, yielding a lower mass density

Question 32

What are the melting and boiling properties molecules like?

Answer 32

They are relatively low melting and boiling temperatures