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48
Room of the Elements · No. 48

Cadmium (Cd): what kind of element is it?

日本語

In short

Cadmium is element number 48, a metal with the symbol Cd. It was found inside zinc, and on the periodic table it sits directly below zinc.
Atomic number 48112.4
CdCadmium (kadomiumu)
Symbol
Cd
Atomic weight
112.4
Place in the table
Period 5 · Group 12

Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.

Found inside zinc

Cadmium was discovered in 1817, in zinc oxide that was being sold. Its name comes from the Greek word for a mineral containing zinc.

Where it sits on the table

Cadmium is in the fifth row of Group 12, with zinc above and mercury below. Both its discovery and its place on the table tie it closely to zinc.

Think about it

There is no single right answer. Talking it over with someone at home is a good way to learn.

Did you know? — Lithium and selenium were also discovered in 1817.
Next steps
About this page
Symbol and atomic weight: Chemical Society of Japan, “Table of Standard Atomic Weights (2026)” and “Table of Atomic Weights with Four Significant Figures (2026)”. Origin of the symbol and year of discovery: Sugiyama, “The Origins of Element Symbols,” Kagaku to Kyōiku 43(12), 1995 (Chemical Society of Japan) (found in commercial zinc oxide). All sources are in Japanese.
Written by CCN CO., LTD.
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