What 3 elements are named after planets?

The three are uranium (named after Uranus), neptunium (Neptune), and plutonium (Pluto). They appear in that order in the periodic table, elements 92, 93, and 94, mirroring the order of the planets in the solar system.

Is mercury named after the planet?

Yes. The element mercury (Hg) shares its name with the planet Mercury and the Roman messenger god the planet is named for. Its chemical symbol, Hg, comes separately from the Latin word 'hydrargyrum,' meaning 'liquid silver.'

What element is named after the Earth?

Tellurium (Te) is named after the Earth, from the Latin word 'tellus.' Selenium was later named after Selene, the Moon, as its counterpart.

Why is plutonium named after Pluto if Pluto is not a planet?

When plutonium was named in 1941, Pluto was still classified as the ninth planet, so it fit the uranium (Uranus) and neptunium (Neptune) naming sequence. Pluto was reclassified as a dwarf planet in 2006, but the element kept its established name.

Elements Named After Planets

When astronomers discovered new worlds in the solar system, chemists discovering new elements often reached for the same names. The clearest example is a run of three: uranium, neptunium, and plutonium mirror the planets Uranus, Neptune, and Pluto in the exact order they appear in the periodic table. A few more elements take their names from other bodies in our solar system: the planet Mercury, the Earth itself, and two minor planets.

The Three Elements Named After Planets

These three elements were named in sequence after the outermost planets, so that increasing atomic number tracks increasing distance from the Sun:

UUranium#92 Uranus

Named after the planet Uranus, discovered in 1781. Martin Heinrich Klaproth named uranium in 1789, just eight years later, to honor the new planet.

NASA/JPL · Public domain

NpNeptunium#93 Neptune

Named after the planet Neptune. Neptunium was the first transuranium element synthesized (1940) and follows uranium in the periodic table just as Neptune follows Uranus.

NASA/JPL · Public domain

Dwarf planet Pluto imaged by New Horizons

PuPlutonium#94 Pluto

Named after Pluto, which was classified as the ninth planet when plutonium was named in 1941. Pluto was reclassified as a dwarf planet in 2006, but the element keeps its name.

NASA/JHUAPL/SwRI · Public domain

Mercury: Planet and God

Mercury is the rare element that shares its name with a planet (and the Roman god the planet is named for):

HgMercury#80 Mercury

Shares its name with the planet Mercury and the swift Roman messenger god, fitting for the only metal that is liquid at room temperature. Its symbol Hg comes from the Latin 'hydrargyrum,' meaning 'liquid silver.'

NASA/JHUAPL/Carnegie · Public domain

Tellurium: Named After the Earth

One element is named after our own planet:

Earth photographed by the Apollo 17 crew (the Blue Marble)

TeTellurium#52 Tellus (Earth)

Named from the Latin 'tellus,' meaning Earth. Selenium was later named after Selene, the Moon, as its deliberate counterpart.

NASA · Public domain

Named After Minor Planets

Two elements are named after minor planets discovered in the early 1800s, just before the elements themselves:

Dwarf planet Ceres imaged by the Dawn spacecraft

CeCerium#58 Ceres

Named after Ceres, the first asteroid discovered (1801) and now classified as a dwarf planet. Cerium was identified in 1803, two years later.

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA · Public domain

PdPalladium#46 Pallas

Named after the asteroid Pallas, discovered in 1802. Palladium was discovered the following year, in 1803.

Why the Planetary Naming Pattern Matters

The uranium-neptunium-plutonium sequence is one of the periodic table's most elegant naming choices. When Edwin McMillan and Glenn Seaborg's teams synthesized elements 93 and 94 in 1940 and 1941, they deliberately continued the planetary order Klaproth had started with uranium 150 years earlier. The pattern is a reminder that element naming is a human, historical act, shaped by what scientists were excited about at the time, from new planets to new gods to one another.