Is It Time to Upend the Periodic Table?

Lothar Meyer, a German chemist, created a partial periodic table in 1864, and a more complete version in 1869. “Structurally, Meyer and Mendeleev’s tables were very similar,” said Alan Rocke, a science historian at Case Western Reserve University, who gave a talk about Meyer at the A.C.S. anniversary symposium.

Initially, the table’s periodicity and its remarkable predictive powers seemed like a “numerological mystery,” Dr. Rocke said. In the 20th century, the periodicity came to be explained by quantum physics — specifically, the physics of how electrons orbit the nucleus. Lithium, sodium and potassium, which nicely align in the table’s first vertical column — Group One, the alkali metals, with rubidium, cesium, and francium — all have one electron in their outer electron shell.

Both chemists constructed many tables over many years, tweaking them in response to new discoveries and better data. Eventually Mendeleev’s won out. When gaps emerged in the patterns of his tables, he made predictions about what should appear. Some were wrong, but he accurately foretold the existence of three elements: gallium, germanium and scandium.

“Prediction is psychologically dramatic,” Dr. Scerri said. “If a scientist predicts something and it comes true, there is a sense in which that scientist knows the secrets of nature, or almost knows the future.”

But science rarely advances by revolution, Dr. Scerri said: “Science is an activity carried out by hundreds of thousands of researchers all contributing to the general picture that eventually emerges.”

That was a theme at the anniversary symposium. Brigitte Van Tiggelen, a chemistry historian at the Science History Institute in Philadelphia, discussed the work of Ida Noddack, a German chemist who discovered rhenium, and Lise Meitner, an Austrian-Swedish physicist who, with Otto Hahn, discovered protactinium. Dr. Tiggelen is an editor of a new book, “Women in Their Element,” that explores more than 30 similar stories, including, of course, that of Marie Curie, who discovered two elements, radium and polonium, and twice won the Nobel Prize.

“We present the story as a communal enterprise,” Dr. Tiggelen said.

Among its many achievements, the periodic table enabled chemistry to finally shed the taint of alchemy. Newton was of little help in this regard: He was obsessed with “chymistry” — synonymous with alchemy, according to the Oxford English Dictionary — and with identifying the philosopher’s stone that would transmute base metals into gold.