Following on from cerium, four more elements named for planets and represented by the classical deities these planets are named for.
Uranium was the first to be named, in 1789 by Martin Klaproth and eight years after the discovery by William Herschel of the planet Uranus. Uranus was the Greek god of the sky, which in ancient times was imagined as a bronze dome studded with stars. Uranium is a naturally-occurring element found in the Earth’s crust but originates in the stars: it is formed in neutron star mergers and supernovae.
After uranium came the discovery of palladium in 1803 by William Hyde Wollaston who named it named after the planet Pallas which had been identifed two years earlier (and is now categorised as an asteroid). Pallas was named for Athena, the Greek goddess of wisdom, who slew the giant Pallas and not only used his skin as a shield but acquired his name as an epithet, becoming known as Pallas Athena. Her symbol was an owl, specifically a Little Owl, which is why the owl has come to represent wisdom in Western culture.
Neptunium is a man-made element, named in 1940 by its discoverers Edwin McMillan and Philip Abelson. The planet Neptune had been discovered way back in 1846 and named for Neptune, the Roman god of the seas who ruled the waves with his trident.
Plutonium followed hot on the heels of neptunium, but although discovered in 1940 by Glenn Seaborg and colleagues, it was not officially published and named until several years later due to war-time secrecy. Pluto the planet (now a dwarf planet) had been discovered in 1930 and, at the suggestion of 11-year old Venetia Burney, named after the ruler of the underworld in classical mythology. Pluto held the keys to the gates of the underworld and thus the key became his attribute.