My Kennedy College students worked tirelessly to climb to the top of the small schools (≤50 students) leaderboard for the Education Perfect Science Championships 2021. The competition is open to schools of any size in Australia and New Zealand. We came first out fo 248 small schools who participated.
I’m very proud of their achievement.
While this competition was online, there will probably be more opportunities to compete with other schools face-to-face in 2022 (depending on covid restrictions!)
Why is Gold yellow? Special relativity causes length contractions and time dilations in objects that travel at speeds approaching the speed of light. The valence electrons of large atoms such as gold have such high energies that their speeds actually approach the speed of light—and the relativistic effects on those electrons can become quite large.
Special relativity changes the energy levels of the 5d orbital in a gold atom so that the energy difference between 5d and 6s orbitals equals the energy of a ‘blue’ photon. Gold thus absorbs blue light when electrons are elevated from the 5d to the 6s orbitals, while other metals do not. These special relativistic changes to the energy levels of atomic orbitals are slightly different for each element.
Relativistic contractions on gold’s valence electrons (the 6s subshell) pull the 6s electron very close to the nucleus. Being closer to the nucleus makes the 6s electron less accessible to any potential reactants. Special relativity is not only the reason for gold’s yellow colour but also for its very low reactivity! ●