What is the atomic number of the element named after Einstein?

The name of the element is ‘Einsteinium’, its symbol is Es and the atomic number is 99. Named in honour of Albert Einstein, it is the seventh transuranic element and does not occur naturally in any measurable quantities. Einsteinium was first identified in December 1952 by Albert Ghiorso, with co-workers at the University of California, Berkeley, when he was examining debris from the first hydrogen bomb test of November 1952.

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Einsteinium is a metallic synthetic element. On the periodic table, it is represented by the symbol Es and atomic number 99. It is the seventh transuranic element, and an actinide. It was named in honor of Albert Einstein.

Its position on the periodic table indicates that its chemical and physical properties are similar to other metals. Though only small amounts have been made, it has been determined to be silver-colored. According to tracer studies conducted at Los Alamos National Laboratory using the isotope 253Es, this element has chemical properties typical of a heavy trivalent, actinide element.

Like all synthetic elements, isotopes of einsteinium are extremely radioactive, and are considered highly toxic.