Roentgenium is element number 111, with the symbol Rg. Its name comes from Wilhelm Röntgen.
Atomic number 111(280)
RgRoentgeniumレントゲニウム (rentogeniumu)
Symbol
Rg
Atomic weight
(280)
Place in the table
Period 7 · Group 11
The number in parentheses is not an atomic weight. It is the mass number of one radioactive isotope of the element.
Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.
Wilhelm Röntgen
Roentgenium was found in Germany in 1995, made by smashing nickel (number 28) into bismuth (number 83). The discovery was confirmed in 2003, and the name was decided in 2004.
Where it sits on the table
Roentgenium is in the seventh row of Group 11, at the bottom of the column with copper, silver and gold.
Think about it
Q1What is 83 + 28?
Q2How many elements named after people can you find in the Room of the Elements?
Q3Can you name the Group 11 elements from the top?
There is no single right answer. Talking it over with someone at home is a good way to learn.
Did you know? — Darmstadtium (110) and roentgenium (111) were both found in Germany in 1995. Both were made with nickel; the only difference was the target, lead or bismuth.