Chem Bonding

Question 1

Why is NaCl soluble in water?

Answer 1

The formation of strong and extensive ion-dipole interactions between Na+ and Cl- ions with water molecules release sufficient energy to overcome the strong ionic bonds in the giant ionic lattice structure of NaCl.

Question 2

Describe metallic bonds.

Answer 2

Metallic bonds are the electrostatic forces of attraction between a lattice of metal cations and a sea of delocalised electrons in giant metallic structure.

Question 3

Describe ionic bonds.

Answer 3

Ionic bonds are the efoa between oppositely charged ions (must state explicitly what ions in qn context) in giant ionic lattice structure.

Question 4

What is the strength of a metallic bond dependent on?

Answer 4

(No. of valence electrons available for delocalisation per atom) / size of metal cation

Question 5

What is the strength of an ionic bond dependent on?

Answer 5

Lattice energy (exothermic), which is proportional to |q+.q- / r+ + r-|.

Question 6

Describe covalent bond.

Answer 6

Covalent bond is the efoa between positively charged nuclei of two (non-metallic) atoms and the shared pair of electrons in simple/giant molecular substances.

Question 7

Compare the bond length between N=O and N-Cl

Answer 7

The bond length of N=O will be shorter than that of N-Cl. There are four electrons in the N=O bond as compared to only two electrons in the N–Cl bond. Hence, there is stronger electrostatic forces of attraction between the bonding electrons and the N and O nuclei, which causes these nuclei to be closer together in the N=O bond.
Thus, the nitrogen-oxygen bond length would be shorter.

Question 8

State the principles of the VSEPR theory.

Answer 8

1. Electron pairs around a central atom are arranged as far apart as possible to minimise repulsion between them.
2. repulsion between lone pair-lone pair of electrons > lone pair-bond pair of electrons > bond pair-bond pair of electrons

Question 9

How to approach questions like “State and explain the bond angles in the molecule of compound ____”?

Answer 9

1. State the VSEPR theory.
2. State the number of bond pairs and lone pairs around the central atom of the molecule.
3. Apply the VSEPR theory: e.g. “Since lp-bp repulsion is greater than bp-bp repulsion, ___ is trigonal planar with a bond angle of 120 degrees”.

Question 10

State the shape of I3- (iodine 3-)

Answer 10

linear

Question 11

In giant molecular structures , the lattice of molecules are held together by strong covalent bonds. T/F?

Answer 11

F. should be lattice of “atoms”, not molecules.

Question 12

What is the state of chlorine at rtp?

Answer 12

Gas

Question 13

What do most people forget when drawing the dot and cross diagram?

Answer 13

the lone pairs on the non-central atoms…