Common questions

Question 1

relative molecular mass

Answer 1

• the average mass of a molecule
• compared to 1/12 of the mass of one atom of carbon-12

Question 2

first ionization energy

Answer 2

the minimum energy required to remove the outermost electron from a neutral atom in gas phase

Question 3

why are compounds of d-block coloured

Answer 3

• unpaired electrons from the d orbitals split into 2 energy levels
• electrons can transition between those states and absorb light of visible wavelengths
• complimentary colour can be observed

Question 4

electronegativity

Answer 4

the ability of an atom to attract a shared pair of electrons in a covalent bond

Question 5

acid-base character of oxides of period 3 elements

Answer 5

Na and Mg oxides are basic
Al oxides amphoteric
Si to Cl oxides are acidic

Question 6

factors affecting electronegativity

Answer 6

• numbers of shells
• nuclear charge
• atomic radius

Question 7

why is zinc not a transition metal

Answer 7

does not have a partially filled d-orbitals, necessary for splitting of transition metals

Question 8

characteristics of transition metals

Answer 8

• variable oxidation states
• partially filled d-orbitals
• catalytic properties
• form coloured compounds

Question 9

Ligand

Answer 9

species with a lone pair of electrons
binds to a metal ion with a dative bond to form a complex

Question 10

metabolic bonding

Answer 10

The electrostatic attraction between a lattice at positive ions and delocalised electrons

Question 11

properties of metabolic bonding

Answer 11

Malleable–The delocalised electrons allow the layer sat positive ions to slide past each other without disrupting the metallic bonding

Question 12

ionic bonding

Answer 12

the electrostatic attraction between oppositely charged ions in a lattice structure

Question 13

properties of ionic bonding

Answer 13

conductor of electricity in liquid state
non conductor of electricity in solid state - rigged lattice

Question 14

metalloid elements

Answer 14

silicon, germanium, arsenic, antimony, tellurium, polonium – staircase from silicon down

Question 15

hybridisation

Answer 15

mixing of atomic orbitals to form molecular orbitals

Question 16

sigma and pi bonds formation

Answer 16

sigma bonds form through the head on overlapping of orbitals along axial symmetry
pi bonds form through the parallel overlapping of orbitals above and below the line drawn through 2 nuclei

Question 17

calorimetry

Answer 17

A technique used to measure the enthalpy associated with a particular change.

assumptions:
- The heat released from the reaction is completely transferred to the water.
- Heat loss to the environment is negligible.
- The maximum temperature reached accurately represents the heat that evolved during the reaction.

Question 18

ionization energy

Answer 18

the energy required to move an electron from the ground state to the infinite level.

Question 19

isomerism

Answer 19

compounds with same molecular formula but different arrangements of the atoms

Question 20

stereoisomerism

Answer 20

different spatial arrangements of atoms in molecules
- configurational: breaking of covalent bonds
- conformational: free rotation about sigma bonds