Chem Bonding

Question 1

covalent bond

Answer 1

Electrostatic forces of attraction between the shared electron and the positively charge nuclei due to the sharing of electrons through overlapping of orbitals

Question 2

dative covalent bond

Answer 2

an atom donates a lone pair of electrons into an empty orbital of another atom for sharing

Question 3

factors affecting strength of covalent bond

Answer 3

1. bond order
   as bond order increases, the number of bonding electrons within the inter-nuclei region increases. the electrostatic forces of attraction for these electrons increases
2. effectiveness overlap of orbitals
   the larger the atom, the larger and more diffused the orbitals, the less effective the overlap of orbitals and the weaker the covalent bond
3. polarity of covalent bond
   the greater the difference in electronegativities of the bonding atoms, the more polar the bond, the stronger the attractive forces between the S+ and S- that strengthens the covalent bond

Question 4

ionic bond

Answer 4

strong electrostatic forces of attraction between oppositely charged ions in giant ionic lattice structure

Question 5

Factors affecting strength of bonds

Answer 5

1. Charge of ions
2. Ionic radius

Greater charge of ions, smaller ionic radius, the stronger the ionic bond.
difference in charge is more important than difference in ionic radius

Question 6

metallic bonds

Answer 6

strong electrostatic forces of attraction between the metal cations and sea of delocalised electrons in giant metallic lattice structure

Question 7

factor affecting strength of metallic bond

Answer 7

1. charge density of the metal cation
   greater the charge and the smaller the size of the ion, the stronger the metallic bond
2. the number of valence electrons
   the large number of valence electrons implies that the large number of sea of delocalised electrons

Question 8

Instantaneous dipole- induced dipole

Answer 8

esfoa between temporary diploles. exist in all simple covalent molecules and noble gases

Question 9

strength of id-id

Answer 9

1. no of electrons
   the larger the no of electron, the more polarisable is the electron cloud, resulting in stronger idid
2. surface area of molecules (isomers)
   straight chain molecule has a larger surface of interaction for more extensive id-id than a branched isomer

Question 10

permanent dipole-permanent dipole

Answer 10

esfoa between polar dipoles which exist between polar molecules

Question 11

strength of pdpd

Answer 11

magnitude of net dipole moment
- difference in electronegativity
- arrangement of polar covalent bonds

Question 12

hydrogen bonds

Answer 12

esfoa between electron-deficient H atom that is bonded to O, F or N atom and lone pair of electrons on a highly electronegative O, F or N atom

Question 13

Strength of H-bonds

Answer 13

1. Polarity of H-X bond
   the more polar the H-X bind, the stronger the H-bond
2. extensiveness of inter-molecular H bonds
   - number of H atoms bonded to N/O/F atom
   - number of lone pairs on N/O/F atom
   - presence of intramolecular H-bond

Question 14

if solute is soluble in solvent

Answer 14

energy that is released from the solute-solvent interaction is sufficient to compensate for energy needed to overcome the solute-solvent and solvent-solute interactions.

Question 15

why are ALCL3, ALBr3 and Be CL2 covalent compounds

Answer 15

they are simple molecule structure due to high charge density of cation and high polarisability of anion.

Question 16

Solubility of ionic compounds

Answer 16

generally soluble due to formation of favourable ion-dipole interactions between ion and water molecules.

some are insoluble due to highly exothermic lattice energy

Question 17

solubility of covalent simple molecules

Answer 17

generally insoluble in water as weak IMF interactions formed with water are weaker than H-bonds between water molecule