A man-made radioactive actinide with atomic symbol Es, and atomic number 99. Its known isotopes range in mass number from 240-258. Its valence can be +2 or +3. Einsteinium was originally discovered in the debris from a thermonuclear explosion in 1952.
A man-made radioactive actinide with atomic symbol Es, and atomic number 99. Its known isotopes range in mass number from 240-258. Its valence can be +2 or +3. Einsteinium was originally discovered in the debris from a thermonuclear explosion in 1952.