Mendelevium

Mendelevium is a special kind of chemical element made by scientists. It has the symbol Md and atomic number 101. This element is a metal that gives off radiation and is part of a group called the actinides.

Mendelevium does not exist in nature and must be made using big science tools called particle accelerators. Scientists first made it in 1955 by shooting einsteinium, another created element, with tiny particles called alpha particles. This is still how it is made today.

Even though scientists can create many mendelevium atoms each hour, this element does not stay around for long. All of its forms disappear quickly. Right now, mendelevium is only used for learning more about science, and only tiny amounts are ever made.

Discovery

Mendelevium was the ninth transuranic element ever made. Scientists first made it in early 1955 at the University of California, Berkeley. A team led by Stanley G. Thompson worked together to make it. They used a special machine called a cyclotron to add atoms to a piece of einsteinium, creating mendelevium.

Because making mendelevium was very hard, the team planned their experiment carefully. They used a special method to find the tiny amount of mendelevium. The element was named "mendelevium" after Dmitri Mendeleev, the scientist who created the periodic table of elements.

Characteristics

Mendelevium is a special metal that does not exist in nature and can only be made in labs. It is part of a group called actinides, found in the periodic table between fermium and nobelium, and below thulium.

Because it is hard to create, scientists have only studied very small amounts of mendelevium. They guess how it might act based on similar elements, and some small experiments support these guesses.

Mendelevium can change when it joins with other elements, acting mostly like other elements in its group. Scientists have also looked at its tiny particles and different versions, called isotopes, which all slowly disappear over time. The version that lasts longest stays for about 51 days, but a version that lasts shorter is often used in experiments because it is easier to make.

Production and isolation

Mendelevium is made by shooting tiny particles at special metals. Lighter versions are created by hitting bismuth with argon ions, while heavier ones come from plutonium and americium struck by carbon and nitrogen ions. The most stable types are made by using einsteinium and shooting it with alpha particles.

Scientists use the movement of these tiny mendelevium atoms to move them away from the material they were made on. They catch the atoms in a gas and move them along a tube for testing. Special chemicals help separate mendelevium from other materials so scientists can study it.

Toxicity

Only a very few people ever come into contact with mendelevium. Experts have set limits on how much of it a person can be exposed to each year. For the most stable form of mendelevium, called mendelevium-258, the limit for eating it is very small — only a tiny amount each year. The limit for breathing it in is also very small. These limits help keep people safe.