State the full electron configuration of \(^{{\text{65}}}{\text{Cu}}\).

State one difference in the physical properties of the isotopes \(^{{\text{63}}}{\text{Cu}}\) and \(^{{\text{65}}}{\text{Cu}}\) and explain why their chemical properties are the same.

Physical:

Chemical:

Describe the bonding in solid copper.

\({\text{1}}{{\text{s}}^{\text{2}}}{\text{2}}{{\text{s}}^{\text{2}}}{\text{2}}{{\text{p}}^{\text{6}}}{\text{3}}{{\text{s}}^{\text{2}}}{\text{3}}{{\text{p}}^{\text{6}}}{\text{3}}{{\text{d}}^{{\text{10}}}}{\text{4}}{{\text{s}}^{\text{1}}}{\text{/1}}{{\text{s}}^{\text{2}}}{\text{2}}{{\text{s}}^{\text{2}}}{\text{2}}{{\text{p}}^{\text{6}}}{\text{3}}{{\text{s}}^{\text{2}}}{\text{3}}{{\text{p}}^{\text{6}}}{\text{4}}{{\text{s}}^{{\text{13}}}}{{\text{d}}^{{\text{10}}}}\);

Physical:

\(^{{\text{63}}}{\text{Cu}}\) lower boiling point/melting point/density/greater rate of diffusion than \(^{{\text{65}}}{\text{Cu}}\);

Accept converse argument.

Do not accept “different mass”.

Chemical:

(properties identical because) same electron configuration/arrangement of electrons;

Accept “same number of protons and electrons”.

Do not accept “same number of electrons” OR “same valence (electrons)” OR “same atomic number” only.

electrostatic attraction;

between (a lattice of) cations/positive ions and delocalized/sea of electrons;

Do not award any mark for only stating “metallic bonding”.

Most were able to quote the electron configuration of copper correctly; but some gave [Ar] \({\text{4}}{{\text{s}}^{\text{1}}}\,{\text{3}}{{\text{d}}^{\text{9}}}\) when they were specifically asked for the full configuration. A few, inevitably gave \({\text{3}}{{\text{d}}^{\text{9}}}\,{\text{4}}{{\text{s}}^{\text{2}}}\). In (b), few related the difference in mass to a property and most did not give the comparison; “the same number of electrons and protons” was more popular than “the same electron configuration”. The descriptions of metallic bonding were disappointing; the mark for electrostatic attraction was rarely scored and many confused “nuclei” with “cations/positive ions”.

Most were able to quote the electron configuration of copper correctly; but some gave [Ar] \({\text{4}}{{\text{s}}^{\text{1}}}\,{\text{3}}{{\text{d}}^{\text{9}}}\) when they were specifically asked for the full configuration. A few, inevitably gave \({\text{3}}{{\text{d}}^{\text{9}}}\,{\text{4}}{{\text{s}}^{\text{2}}}\). In (b), few related the difference in mass to a property and most did not give the comparison; “the same number of electrons and protons” was more popular than “the same electron configuration”. The descriptions of metallic bonding were disappointing; the mark for electrostatic attraction was rarely scored and many confused “nuclei” with “cations/positive ions”.

Most were able to quote the electron configuration of copper correctly; but some gave [Ar] \({\text{4}}{{\text{s}}^{\text{1}}}\,{\text{3}}{{\text{d}}^{\text{9}}}\) when they were specifically asked for the full configuration. A few, inevitably gave \({\text{3}}{{\text{d}}^{\text{9}}}\,{\text{4}}{{\text{s}}^{\text{2}}}\). In (b), few related the difference in mass to a property and most did not give the comparison; “the same number of electrons and protons” was more popular than “the same electron configuration”. The descriptions of metallic bonding were disappointing; the mark for electrostatic attraction was rarely scored and many confused “nuclei” with “cations/positive ions”.