Recall Sem1: Chemical Bonding

Elements X, Y and Z are all in the first two periods of the Periodic Table. Their Pauling electronegativity values, E_N are shown.
Increasing melting point in order of Z₂ < YZ < XZ.

• TRUE

• FALSE

Ammonium carbonate contains ionic, single covalent and dative bonds.

• TRUE

• FALSE

Which molecule contains a nitrogen atom with sp hybridisation?

• CH₃CH₂NH₂

• HNO₃

• HCN

• NH₃

Which species have different shape from others?

• CH₄

• NH₄⁺

• SCl₄

• SiCl₄

Which of the following is not a reason of chloromethane is a polar molecule?

• C and Cl have different electronegativity.

• C-Cl is polar bond.

• dipole moments cannot be cancelled out each other.

• Cl has lone pairs.

At room conditions, water exists as liquid while ammonia exists as gas.

Which could be the reason?

• Stronger intermolecular forces in water.

• Stronger O-H bonds.

• Stronger attraction between nucleus and outer electrons in oxygen.

• Stronger strength of electrophile