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Einsteinium (Es) – Element 99 of the periodic table

Einsteinium (symbol Es) is element number 99 of the periodic table and belongs to the “Actinide” category. Its atomic mass is about 252, and its phase under standard conditions is Solid. This element sits in period 7 and the f-block (Actinides) of the periodic table, and its electrons are arranged in shells of 2, 8, 18, 32, 29, 8, 2. The short electron configuration of Einsteinium is [Rn] 5f¹¹ 7s². Known uses of Einsteinium include Scientific research.

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Einsteinium is a radioactive, mostly synthetic element; its data may be based on limited experiments or theoretical prediction.

Properties of Einsteinium

Atomic number
99
Chemical symbol
Es
Atomic mass
252
Category
Actinide
Period
7
Block
f
Phase
Solid
Protons
99
Electrons
99
Neutrons (approx.)
153
Electron shells
2, 8, 18, 32, 29, 8, 2
Outer-shell electrons
2
Discovered
Albert Ghiorso (1952)

Electron configuration of Einsteinium

The electron configuration of Einsteinium (Es), with 99 electrons, is shown below. The last shell (shell 7) is highlighted:

Full configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹¹ 6s² 6p⁶ 7s²
Short configuration
[Rn] 5f¹¹ 7s²
Last shell
7s²

What is electron configuration and how is it written?

Electron shells of Einsteinium

Distribution of 99 electrons of Einsteinium across shells K to Q:

  1. K2
  2. L8
  3. M18
  4. N32
  5. O29
  6. P8
  7. Q2

What is a actinide?

The actinides are the 15 elements from actinium to lawrencium, part of the f-block, and all of them are radioactive.

Uses of Einsteinium

Frequently asked questions about Einsteinium

What is the atomic number of Einsteinium?

The atomic number of Einsteinium (Es) is 99; that is, every atom of it has 99 protons.

What is the electron configuration of Einsteinium?

The electron configuration of Einsteinium (Es) is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹¹ 6s² 6p⁶ 7s²; in short form it is [Rn] 5f¹¹ 7s², and its last shell is 7s².

What is the chemical symbol of Einsteinium?

The chemical symbol of Einsteinium is Es.

Where is Einsteinium located in the periodic table?

Einsteinium is located in period 7 and the f-block (Actinides) and belongs to the “Actinide” category.

What is the atomic mass of Einsteinium?

The atomic mass of Einsteinium is about 252 (atomic mass units).

What is the phase of Einsteinium under normal conditions?

The phase of Einsteinium under standard conditions is Solid.

What are the uses of Einsteinium?

Uses of Einsteinium include Scientific research.

Who discovered Einsteinium?

Einsteinium was discovered by Albert Ghiorso in 1952.

Elements in the same category as Einsteinium (Actinide)

Actinium (Ac)Thorium (Th)Protactinium (Pa)Uranium (U)Neptunium (Np)Plutonium (Pu)Americium (Am)Curium (Cm)Berkelium (Bk)Californium (Cf)Fermium (Fm)Mendelevium (Md)Nobelium (No)Lawrencium (Lr)

See all Actinides