Americium (Am) – Periodic Table (Element Information & More)

This is a SUPER easy guide on Americium element.

In fact, the table mentioned below is the perfect information box (Which gives you every single detail about the Americium element in Periodic table.)

So if you want to know anything about Americium element, then this guide is for you.

Let’s finish this very quickly.

Americium Element (Am) Information

Appearance	Silvery-white metallic appearance
State (at STP)	Solid
Position in Periodic table	Group: actinides, Period: 7, Block: f
Category	Inner transition metals
Atomic number or  Protons	95
Neutrons	148
Electrons	95
Symbol	Am
Atomic mass of Americium (most stable isotope)	243 u
Electrons arrangement or  Bohr model	2, 8, 18, 32, 25, 8, 2
Electronic configuration	[Rn] 5f7 7s2
Atomic radius	244 picometers (van der Waals radius)
1st Ionization energy	5.993 eV
Electronegativity	1.3 (Pauling scale)
Crystal structure	Double hexagonal close packed
Melting point	1449 K or 1176 °C or 2149 °F
Boiling point	2880 K or 2607 °C or 4725 °F
Density	13.67 g/cm3
Main isotopes	241Am and 243Am
Who discovered Americium and when?	Glenn T. Seaborg, Albert Ghiorso, Leon O. Morgan, Ralph A. James (in 1944)
CAS number	7440-35-9

Americium in Periodic table

Americium element is in period 7 and in actinides group of the Periodic table. Americium is the f-block element and it belongs to inner transition metals group.

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Why is Americium in Period 7?

Let me ask you a question.

How many shells does americium have?

It’s 7. Right?

You have already seen the bohr model of americium atom in the above table.

From the Bohr model, it can be found that the number of orbits or shells in americium is 7. Hence, as americium has 7 orbits, it lies in period 7 of the Periodic table. 

Why is Americium in f-block?

Before knowing this reason, first of all I want to ask you a simple question.

How can you determine the blocks-wise position of elements?

The simple answer: The elements will lie in the s, p, d or f block will completely depend upon the subshell in which the last electron will enter.

For example; the electron configuration of americium is [Rn] 5f⁷ 7s².

So the last electron of americium enters the f-subshell or f-orbital. 

Hence, americium is the f-block element.

5 Interesting facts about Americium

Interesting facts about americium element are mentioned below.

1. The name “Americium” was derived from “America”.
2. Americium was discovered by Glenn T. Seaborg, Albert Ghiorso, Leon O. Morgan and Ralph A. James in 1944.
3. Americium element is generally produced artificially in laboratory, but it also occurs naturally in trace amounts in uranium ores.
4. Americium has around 19 isotopes and all those isotopes are radioactive in nature.
5. Out of many isotopes of americium, the most stable isotope is ²⁴³Am, which has a half life of 7370 years.

Properties of Americium

The physical and chemical properties of americium element are mentioned below.

Physical properties of Americium

Physical properties of americium are mentioned below.

• Americium is a solid metal having a silvery-white metallic appearance.
• The density of americium metal is 13.67 g/cm³, which is near to the density of mercury at room temperature.
• The calculated melting points and boiling points of americium element are 1176 °C and 2607 °C respectively.
• The crystal structure of americium is double hexagonal close packed.

Chemical properties of Americium

Chemical properties of americium are mentioned below.

• Americium is radioactive as well as toxic metal.
• When pure americium metal is kept open in the dry air, it starts tarnishing due to reaction with oxygen.
• There are many oxidation states of americium ranging from +2 to +7, but its most stable oxidation state is +3.

Uses of Americium

The uses of americium are mentioned below.

• Americium dioxide, which contains the isotope ²⁴¹Am, is used in household smoke detectors.
• ²⁴¹Am is a good source of gamma rays and hence it is used in some medical applications as well as other industrial applications.
• Americium is used for production of other transuranic elements.
• It is also used as a fuel in spacecraft batteries.

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External resources:

1. Americium – Wikipedia. (2023, February 11). Americium – Wikipedia. https://en.wikipedia.org/wiki/Americium
2. Americium – Element information, properties and uses | Periodic Table. (n.d.). Americium – Element Information, Properties and Uses | Periodic Table. https://www.rsc.org/periodic-table/element/95/americium
3. P. (n.d.). Americium | Am (Element) – PubChem. Americium | Am (Element) – PubChem. https://pubchem.ncbi.nlm.nih.gov/element/Americium
4. It’s Elemental – The Element Americium. (n.d.). It’s Elemental – the Element Americium. https://education.jlab.org/itselemental/ele095.html
5. Radionuclide Basics: Americium-241 | US EPA. (2015, April 14). US EPA. https://www.epa.gov/radiation/radionuclide-basics-americium-241
6. Americium | CCDC. (n.d.). Americium | CCDC. https://www.ccdc.cam.ac.uk/elements/americium/