3A - Periodicity
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3A - Periodicity |
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1) What are the similarities in the electron configuration for the atoms of Group 7? [1]
All have p5
2) a) Define first ionisation energy [3]
The energy required to remove one electron from each atom [1]
in 1 mole of gaseous atoms [1] to form 1 mole of gaseous 1+ ions [1]
b) Explain the trends in atomic radius across a period [4]
Across period nuclear charge increases [1] Electrons in same shell, shielding remains the same [1]
Greater attraction [1] Atomic radius decreases [1]
c) Use your answer in (a) to explain the trends in 1st ionisation energies across a period? [5]
Across period nuclear charge increases [1] Electrons in same shell, shielding remains the same [1]
Greater attraction [1] Atomic radius decreases [1] Electrons more difficult to remove [1]
3) a) Explain the trends in atomic radius down a Group. [3]
More electron shells [1] More shielding [1] Atomic radii increases [1]
b) Use your answer in (a) to explain the trends in 1st ionisation energies down a Group? [4]
More electron shells [1] More shielding [1] Atomic radii increases [1]
Attraction decreases despite an increase in the nuclear charge [1]
4) a) Why is the melting point of magnesium greater than that of sodium? [3]
As you go across Period, metal ions have a larger charge [1] Also has more delocalised electrons [1]
Attraction is greater between larger ionic charge and more delocalised electrons [1]
b) Why is the boiling point of carbon greater than that of oxygen? [4]
Carbon: Giant covalent structure, extensive strong covalent bonds [1]
Lots of energy required to break covalent bonds [1]
Oxygen: Simple molecular – weak IMF – VDW [1] Less energy required [1]