The lanthanides
The lanthanides: a chapter of The Periodic Table Book, with each element's symbol, number and story.
16 cards · Science
Each Zap teaches up to 5 new cards, so you learn the chapter a few at a time.
Checked by the Brain Zap team · reviewed 27 Oct 2026
Sources: Periodic Table of Elements (IUPAC), Periodic Table (Royal Society of Chemistry)
Preview
Symbol: La
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Lanthanum
Learn more: Its name means to lie hidden, as it hid in other minerals; it is used in camera lenses.
Symbol: Ce
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Cerium
Learn more: The most common rare earth; mixed with iron, it makes the flint in lighters.
Symbol: Pr
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Praseodymium
Learn more: It was found with neodymium as a single substance, didymium, which was split in two in 1885.
Element 60
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Neodymium
Learn more: Neodymium magnets, the strongest kind, are in headphones, electric cars and wind turbines.
Symbol: Pm
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Promethium
Learn more: Every form of it is radioactive, so almost none exists in nature; it is named after Prometheus.
About this topic
The lanthanides, elements 57 to 71, sit in a row of their own below the main table. They are often called rare earths, though most aren't rare: they hide mixed together in the same minerals and were very hard to separate. Today they are everywhere: in the strongest magnets, in the glow of screens, in the cables that carry the internet, and on euro banknotes. Four of them are named after one Swedish village.
This is a chapter of The Periodic Table Book. Each card shows a symbol or an atomic number and asks for the element's name, with a hint before you answer and a fact after.
All 16 cards
Symbol: La
Lanthanum
Learn more: Its name means to lie hidden, as it hid in other minerals; it is used in camera lenses.
Symbol: Ce
Cerium
Learn more: The most common rare earth; mixed with iron, it makes the flint in lighters.
Symbol: Pr
Praseodymium
Learn more: It was found with neodymium as a single substance, didymium, which was split in two in 1885.
Element 60
Neodymium
Learn more: Neodymium magnets, the strongest kind, are in headphones, electric cars and wind turbines.
Symbol: Pm
Promethium
Learn more: Every form of it is radioactive, so almost none exists in nature; it is named after Prometheus.
Symbol: Sm
Samarium
Learn more: The first element named after a person, the mining engineer Samarsky-Bykhovets, through a mineral.
Symbol: Eu
Europium
Learn more: Euro banknotes glow under UV light thanks to europium compounds in their ink.
Symbol: Gd
Gadolinium
Learn more: Named after the chemist Johan Gadolin; injected in compounds, it sharpens MRI images.
Symbol: Tb
Terbium
Learn more: Named after the Swedish village of Ytterby; it gives a bright green glow in lamps and screens.
Symbol: Dy
Dysprosium
Learn more: Chemists needed many tries to separate it, hence its Greek name; it keeps magnets strong when hot.
Symbol: Ho
Holmium
Learn more: Holmia is Latin for Stockholm; it is among the most magnetic of all elements.
Symbol: Er
Erbium
Learn more: Erbium-doped fibre amplifies the light that carries internet data under the oceans.
Symbol: Tm
Thulium
Learn more: Thule was the far north on ancient maps; it is one of the rarest of the rare earths.
Element 70
Ytterbium
Learn more: The fourth element named after Ytterby; it is used in some of the most precise atomic clocks.
Symbol: Lu
Lutetium
Learn more: Lutetia is the Latin name of Paris, where it was found in 1907.
Name often given to the lanthanides
Rare earth elements
Learn more: They hide mixed together in the same minerals and are hard to separate, which made them seem rare.
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