L10: Metallic & Intermolecular Bonding Flashcards Preview

Chemistry (Semester 1) > L10: Metallic & Intermolecular Bonding > Flashcards

Flashcards in L10: Metallic & Intermolecular Bonding Deck (32):
1

Describe the interactions in metallic bonding

Electrostatic attraction between metal ions and mobile, delocalised electrons

2

What are delocalised electrons?

They are not associated with a particular atom

3

What are the prerequisites for metallic bonding to occur?

1) The metal should have low ionisation energies (able to give up their electrons to form positive metal ions)

2) The metal should have vacant valence orbitals to allow free movement of electrons

4

Fill in the gap:

Metallically bonded compounds are __(1)__ conductors of heat and electricity in in solid and __(2)__ state

(1) good
(2) liquid

5

Comment on the lustre of metallic compounds

Metallic compounds have a high lustre

6

True or false: Metallic compounds are relatively malleable and ductile

True

7

What are intramolecular forces?

Bonds holding atoms together within a molecule

8

What are intermolecular forces?

Attractive forces between molecules

9

Which is stronger, intermolecular or intramolecular forces?

Intramolecular

10

What are the four types of intermolecular forces? List in order of strength (strongest first)

1) Ion-dipole
2) Hydrogen bonds
3) Dipole-dipole
4) Dispersion

11

Which bonds form between polar molecules?

Ion-dipole, hydrogen, and dipole-dipole

12

Which bonds form between non-polar molecules?

Dispersion (van der Waals/London)

13

True or false: London dispersion forces are formed between temporary dipoles. These dipoles come about because of the uneven distribution of electrons in their orbitals

True

14

True or false: London dispersion forces form between temporary dipoles

True

15

True or false: Dipole-dipole interactions form between temporary dipoles

False. They relate to permanent dipoles

16

True or false: Dipole-dipole interactions act in addition to Van der Waals

True

17

How do dipole-dipole interactions effect boiling point?

Result in higher BP than expected from the mass of the molecule

18

In which two areas are dipole-dipole interactions significant?

1) Carbonyls
2) Protein folding

19

Fill in the gaps:

__(1)__-dipole forces are electrostatic interactions between an __(2)__ and an __(3)__ __(4)__ molecule

(1) ion
(2) ion
(3) uncharged
(4) polar

20

What factor effects the strength of an ion-dipole bond?

Strength depends on the charge on the ion and the magnitude of the dipole

21

Where are ion-dipole forces most common?

In solution.

E.g. NaCl dissolving in water

22

What are the two requirements for a hydrogen bond?

1) An electronegative atom (O, N, or F) to act as the acceptor

2) A hydrogen atom in a polar bond (N-H, O-H, or F-H) to act as the donor

23

True or false: Hydrogen bonds are stronger than other dipole-dipole interactions

True

24

True or false: Hydrogen bonds are non-directional

False. Hydrogen bonds are directional

25

True or false: Although they are relatively strong for intermolecular forces, hydrogen bonds are weak and easily broken compared to covalent bonds

True

26

Give six areas in which hydrogen bonding plays a significant role

1) Physical state of water

2) Stabilise macromolecules

3) DNA double helix, base pairing

4) Protein secondary structure; alpha helices, beta sheets

5) Enzyme-substrate and antibody-antigen interactions

6) Solubility of compounds in water

27

Why does water form such an extensive network of hydrogen bonds?

Each oxygen atom has two lone pairs and each molecule has two hydrogen atoms

28

True or false: The base pairs match each other based on the number of hydrogen bonds each can donate/accept

True

29

True or false: In alpha helices and beta sheets, hydrogen bonds form between amine (N-H) and C=O

True

30

In addition to hydrogen bonds, what links can be formed by covalent and ionic bonding in secondary protein structures?

Covalent disulphide links (R-S-S-R)

Ionic salt bridges (---CO2----NH3----

31

Which intermolecular bonds hold sugar chains together in cellulose to form flat sheets?

Hydrogen bonds

32

Which intermolecular bonds hold flat sheets of hydrogen-bonded sugar chains together in cellulose?

Van der Waals