Periodic table

The periodic table was a list of elements.

Captain Christina Morgenstern identified six elements from six alien periodic tables in the Hen's Tooth nebula. (PROSE: Grimm Reality)

According to the Fourth Doctor, the periodic table was first published in 1872 and had many scientific revelations in it. When archaeologist Horace Stockwood wasn't familiar with it, the Doctor stated that "anyone who claims to be a scientist and who hasn't heard of the periodic table is not so much walking as crawling - rather rapidly back into the Dark Ages." (PROSE: Eye of Heaven)

In the 1955, ten-year-old Henry Bergson wanted a chemistry set for Christmas but his father didn't believe in him and claimed he couldn't afford it. In this timeline, Henry Bergson ended up homeless by 1975 but could still remember every component of the set, including a poster of the periodic table. The Seventh Doctor and his companions altered the timeline by giving Henry the chemistry set as a child, leading to him becoming an important biologist whose research defeated a Kellenian invasion of Earth. (PROSE: Presence)

Archaeologist Ernest Fleetward discovered parts of a humanoid skeleton around the world made of crystals which did not fit in the periodic table and established crystallography. The Eighth Doctor convinced him to present his findings in early 2004. (PROSE: Sometime Never...)

Toshiko Sato's metallurgy tests on a Vondraxian orb revealed that it shared properties with titanium and zinc but the actual metal was found nowhere on the periodic table. (PROSE: Trace Memory)

When history teacher Barbara Wright teased Ian Chesterton for not having learned the British monarchy as a schoolboy, the science retorted about schoolgirls not learning the periodic table. (PROSE: The Plotters)

There was a periodic table on the wall of Chris Parsons' lab. (TV: Shada)

Zoe Heriot regarded tellurium as an "exceptional element" on the periodic table. (TV: The Krotons)

When the Eighth Doctor had partial amnesia, he could remember "useless bits of information" like the periodic table. (PROSE: Halflife) He could even sing the periodic table to the tune of "The Modern Major General". (PROSE: Grimm Reality)

Technical Services Supervisor Alex Bannen analyses indicated all super-heavy elements of the periodic table were abundant on Lucifer and were used to power the Lift and Moloch's interior sun. His goal for Project Eden was to get the Angels to tell him how and where they were produced and stabilized as well as obtaining samples. (PROSE: Lucifer Rising)

Chief Scientist Whitfield could recite the whole periodic table as a child. This fact helped her know she was the same person after using a transmat that broke her body down at one end and reassembled it on the other. (PROSE: Cold Fusion)

Bernice Summerfield knew that teaching machines could make you know the elements in the periodic table but not how to apply the list of information. (PROSE: A Game of Soldiers)

An incarnation of the Doctor from and alternate universe saw a copy of the periodic table in Pallant's diary. (PROSE: The Infinity Doctors)

Behind the scenes
The Eighth Doctor references "The Elements" by Tom Lehrer in PROSE: Grimm Reality.