Hello everybody - and welcome to the Chemical Elements! Today, we'll cover the first radioactive element to be discovered...
If you are confused by any of these terms, go to the glossary!
Facts about radium
Symbol: Ra
Electron configuration: [Rn] 7s2
Atomic number: 88
Key isotope: 226Ra
Relative atomic mass: [226]
Melting point: 696 °C
Boiling point: 1500 °C
Electronegativity: 0.9
1st ionisation energy: 509.29 kJ mol-1
(226Ra only)
☢ Half-life: 1,600 years
☢ Decay product: 222Rn
The year was 1898. There was the uranium ore pitchblende (uranium oxide, U3O8). And there was Marie and Pierre Curie. With all the known methods of chemical separation known at the time, they managed to extract 1 milligram of a new element. They named it radium, from the Latin radius (meaning ray) for the way it glowed in the dark.
Let's get something straight here. Radium was not the first radioactive element to be discovered. That honour goes to uranium. It was, however, the first element to have its radioactivity discovered. (In other words, they found out radium is radioactive before uranium.)
Marie and Pierre Curie were unfortunately killed by radium. They did so many experiments with it that they ended up falling victim to radiation poisoning. Radium also happens to be the element that created the media image of radioactive elements as glowing green; radium paint does glow green, but pure radium metal glows... blue. Bit of a difference in colour, then!
Radium paint was fairly often used around 100 years ago. They used it in glow-in-the-dark watches and clocks. Nowadays, it's considered too toxic to be used in these applications. They kind of did a switch-around; they first replaced radium with promethium (147Pm), which was safer, and then replaced promethium with tritium (3H).
Yep - radium is a metal, a solid metal, that used to be used in glowing paint, but not anymore.
Electron configuration: [Rn] 7s2
Atomic number: 88
Key isotope: 226Ra
Relative atomic mass: [226]
Melting point: 696 °C
Boiling point: 1500 °C
Electronegativity: 0.9
1st ionisation energy: 509.29 kJ mol-1
(226Ra only)
☢ Half-life: 1,600 years
☢ Decay product: 222Rn
Let's get something straight here. Radium was not the first radioactive element to be discovered. That honour goes to uranium. It was, however, the first element to have its radioactivity discovered. (In other words, they found out radium is radioactive before uranium.)
Marie and Pierre Curie were unfortunately killed by radium. They did so many experiments with it that they ended up falling victim to radiation poisoning. Radium also happens to be the element that created the media image of radioactive elements as glowing green; radium paint does glow green, but pure radium metal glows... blue. Bit of a difference in colour, then!
Radium paint was fairly often used around 100 years ago. They used it in glow-in-the-dark watches and clocks. Nowadays, it's considered too toxic to be used in these applications. They kind of did a switch-around; they first replaced radium with promethium (147Pm), which was safer, and then replaced promethium with tritium (3H).
Yep - radium is a metal, a solid metal, that used to be used in glowing paint, but not anymore.
I have some news...
I have come to see my relatives in Ireland - and have gotten a holiday out of it, too!
We left the house at 5am and drove to Holyhead in Wales, where we got the ferry to Dublin. Then we went from Dublin to my relatives' house! I had fun yesterday, and the week ahead looks to be full of fun, too. I'm really looking forward to having a fun-filled week in Ireland!
Anyway, that's all from me for this week. I'll see everybody next Sunday, so until then, stay safe!