Mendelevium

Mendelevium is a special kind of chemical element that scientists create in laboratories. It has the symbol Md and atomic number 101. This element is a metal that gives off radiation and belongs to a group called the actinides.

Mendelevium cannot be found 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 created 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. They managed to make seventeen atoms of mendelevium, which is very few!

Because making mendelevium was so hard, the team needed to carefully plan their experiment. They calculated that they would only get one atom of mendelevium each time they tried. They used a special method to separate the tiny amount of mendelevium from other materials. On February 19, they finally saw proof that they had created mendelevium by watching how it broke apart.

The element was named "mendelevium" after Dmitri Mendeleev, the scientist who created the periodic table of elements. Even though it was during a time when the United States and Russia did not always agree, the team was allowed to name the element after him.

Characteristics

Mendelevium is a special kind of metal that is not found naturally and can only be created in laboratories. It is part of a group of elements called actinides, placed in the periodic table between fermium and nobelium, and below thulium.

Because it is very hard to make, scientists have only been able to study tiny amounts of mendelevium. They have made predictions about how it might behave based on what they know about similar elements. Some experiments with very small samples have supported these ideas.

Mendelevium can exist in different forms when it combines with other elements, mostly showing behaviors similar to other elements in its group. Researchers have also studied its tiny particles and different versions, called isotopes, which all break down over time. The version that lasts the longest stays around for about 51 days, but a shorter-lasting version is often used in experiments because it can be made more easily.

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 target material. They catch the atoms in a gas and carry them along a tube for testing and measuring. Special chemicals help separate mendelevium from other materials so scientists can study it further.

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 from any possible harm.