Americium

ACTINIDE

Bohr Model: Electrons arranged in energy shells around the nucleus.

Americium is a radioactive transuranic chemical element with symbol Am and atomic number 95. This member of the actinide series is located in the periodic table under the lanthanide element europium, and thus by analogy was named after the Americas. Americium was first produced in 1944 by the group of Glenn T.Seaborg from Berkeley, California, at the metallurgical laboratory of University of Chicago.

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Quick Facts

Atomic Number 95

Period 7

Group 9

Phase Solid

Appearance silvery white

About Actinides

Actinides are the 15 metallic elements with atomic numbers 89–103. All actinides are radioactive.

History

Discovered By Glenn T. Seaborg

Named By Unknown

Physical Properties

Atomic Mass 243

Density 12 g/L

Molar Heat 62.7 J/(mol·K)

Phase Transition (Melting & Boiling Points)

Americium melts at 1449 K and boils at 2880 K.

Atomic Properties

Electron Config [Rn] 5f7 7s2

Electronegativity 1.13

Electron Affinity 9.93 kJ/mol

Ionization Energy 578 kJ/mol

Orbital Filling Diagram

This diagram visualizes electron configuration according to the Aufbau principle and Hund's rule. Boxes represent orbitals (s, p, d, f), while arrows indicate electrons with spin up or down. Electrons fill lower energy levels first and occupy orbitals singly before pairing.

Emission Spectrum Emission spectrum of Americium

Photograph

Source: Wikipedia

External Resources

Wikipedia PubChem Royal Society of Chemistry Periodic Videos (YouTube)

Study Guide

Atomic Number

The number of protons in the nucleus, which defines the element.

Atomic Mass

The average mass of an atom, including protons and neutrons.

Electronegativity

A measure of how strongly an atom attracts electrons in a bond.

Ionization Energy

The energy required to remove an electron from an atom.

Electron Config

The arrangement of electrons in the atom's energy shells.