Copper is element number 29, a metal with the symbol Cu. A ten-yen coin is 95% copper. On the periodic table, copper sits in Group 11 with silver and gold.
Atomic number 2963.55
CuCopper銅 (dō)
Symbol
Cu
Atomic weight
63.55
Place in the table
Period 4 · Group 11
Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.
Copper in coins
The ten-yen coin is bronze: out of every 1,000 parts, 950 are copper, 30–40 zinc and 10–20 tin. The five-yen coin is brass, made of copper and zinc. The 100-yen and 50-yen coins are cupronickel, copper and nickel.
Of the six coins Japan makes today, every coin except the one-yen coin contains copper.
A symbol from an island
The symbol Cu comes from the Latin cuprum, from the name of Cyprus, a Mediterranean island once known for its copper. Copper has been known since ancient times.
In Japanese ninth-grade science, one example experiment is building a Daniell cell with a zinc plate and a copper plate and confirming that it produces a voltage.
An adult body contains about 100 mg of copper.
Think about it
Q1Why do ten-yen coins sometimes turn brownish or dark?
Q2Why do you think copper is so often used for coins?
Q3Gold, silver and copper are in the same column. Do you think that is a coincidence?
There is no single right answer. Talking it over with someone at home is a good way to learn.
Did you know? — Of the roughly 100 mg of copper in an adult body, about 65% is in the muscles and bones and about 10% is in the liver.