Americium

Americium, an element with an atomic number of 95, is a white, silvery metal that remains solid at 20°C. It is primarily produced in nuclear reactors. Americium has various applications, including its use in smoke detectors and flat glass production. However, it can pose significant risks to human health and the environment.

1.0Introduction

Americium is a synthetic actinide element with an atomic number of 95 in the periodic table. Notably, it has no stable isotopes. This element was discovered in 1944 by Glenn Seaborg, Leon Morgan, Ralph James, and Albert Ghiorso and was later isolated by B.B. Cunningham as the isotope ²⁴¹Am in Am(OH)₃ during the fall of 1945.

Americium was named to honour the Americas (Seaborg, 1991; Seaborg and Loveland, 1990). Actinides, the group to which americium belongs, consist of 15 elements ranging from actinium (atomic number 89) to lawrencium (atomic number 103).

2.0Physical Properties of Americium 

3.0Chemical Properties of Americium

1. Reaction with Oxygen
   Americium reacts with oxygen to form americium oxide (AmO₂), a red-brown solid. In this reaction, americium exhibits an oxidation state of +4:
   Am (s) + O₂ → AmO₂​
2. Reaction with Halogens
   Americium reacts with halogens to form americium halides. For instance, when americium reacts with fluorine, it forms americium tetrafluoride (AmF₄). In this reaction, americium also exhibits an oxidation state of +4:
   Am (s) + 4F→ AmF₄

4.0Production of Americium

Americium-241 is synthesized through a series of neutron capture and beta decay reactions involving plutonium isotopes. The detailed steps are as follows:

1. Initial Neutron Capture

• Plutonium-239 (Pu-239) absorbs a neutron in a nuclear reactor: 

Pu-239+n→Pu-240

• Result: Plutonium-240 is formed.

2. Second Neutron Capture

• Plutonium-240 (Pu-240) absorbs another neutron:

 Pu-240+n→Pu-241

• Result: Plutonium-241 is produced.

3. Beta Decay of Plutonium-241

• Plutonium-241 undergoes beta decay to form Americium-241 (Am-241): Pu-241→β−Am-241+e−

In this process:

• A neutron in the Pu-241 nucleus is converted into a proton, emitting a beta particle (e⁻) and an antineutrino (νˉe\bar{\nu}_eνˉe​).
• This increases the atomic number by 1, resulting in the formation of Americium-241.