I'm not sure about the 'platinum group of metals' but have a fair knowledge of the Periodic Table (rote memorization in high school).

Re(agan)(d)O(e)s Ir(rational) (s)P(it)t(ing)in his A(wf)u(l) speeches. This was 75-79 (we memorized in groups of 5).

Rhenium, Osmium, Iridium, Platinum and Gold. I know Mercury comes after Gold, so have I come close to the correct six?