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Fermium

Table Of Contents

What is Fermium
History of the Element
Fermium Identification
Properties and Characteristics of Fermium
Atomic Data of Fermium (Element 100)
Uses of Fermium
Health Hazards
Interesting Facts
Cost of Fermium

What is Fermium

Fermium (pronounced as FER-mee-em) ^[2] is a synthetic, transuranium, radioactive element ^[3] with the symbol Fm [1] belonging to the family of inner transition metals ^[10]. It has 18 isotopes with mass numbers ranging from 242 to 259 of which Fm-257 is the most stable isotope with a half-life of 100.5 days ^{[2, 3]}. It decays into californium-253 through alpha emission and spontaneous fission ^[2].

Fermium Symbol

Where Is it Found

It cannot be found naturally on earth ^[3]. However, it can be obtained in microgram quantities by the neutron bombardment of plutonium in a nuclear reactor ^[1].

History of the Element

Origin of the Name: The element is named after the famous nuclear physicist Enrico Fermi ^[1].

Who Discovered it: It was discovered by a team of scientists led by Albert Ghiorso on October 31, 1952 ^{[2, 3]}.

How was it Discovered

The first isotope of fermium (later named as fermium-255), was found in the nuclear debris after the thermonuclear explosion of the first hydrogen bomb (codenamed Ivy Mike ^{[3, 10]}) on an atoll in the Pacific Ocean ^[1]. It was because uranium-238, the source of heat for the detonation, was exposed to a flux of neutrons during the process and combined with 17 of them to produce Fm-255 that has a half-life of about 20 hours ^{[1, 2]}.

It was later produced in the laboratory by a group at the Nobel Institute of Stockholm. They bombarded uranium-238 with oxygen nuclei producing fermium-250 with a half-life of 30 minutes ^[1].

Fermium Identification
Atomic Number	100 ^[2]
CAS Number	7440-72-4 ^[1]
Position in the periodic table	Group: Actinides^[1]	Period: 7 ^[1]	Block: f ^[1]

Location of Fermium in the Periodic Table

Properties and Characteristics of Fermium

General Properties
Atomic mass	257 atomic mass units ^[8,9]
Mass number	257 ^[5]
Physical Properties
Color/appearance	Unknown ^[3,7]
Luster	Unknown ^[16]
Texture	Unknown ^[14]
Melting point/freezing point	1527°C (2781°F) ^[1]
Boiling point	Unknown ^[1]
Density	Unknown ^[1]
State of matter at room temperature (natural state)	Solid ^[1,2]
Hardness	Unknown ^{[12, 15]}
Chemical Properties
Flammability		Unknown
Oxidation state/Oxidation number		+2, +3 ^[1]
Reactivity		Unknown ^[13]

Atomic Data of Fermium (Element 100)

Valence electrons	2 ^[4]
Quantum numbers
– n	5 ^[4]
– ℓ	3 ^[4]
– m_ℓ	1 ^[4]
– m_s	-½ ^[4]
Electron configuration (noble gas configuration)	[Rn]5f¹²7s² ^[3]
Atomic structure
– Number of Electrons	100 ^[3]
– Number of Neutrons	157 ^[3]
– Number of Protons	100 ^[3]
Energy levels
– First Energy Level	2 ^[3]
– Second Energy Level	8 ^[3]
– Third Energy Level	18 ^[3]
– Fourth Energy Level	32 ^[3]
– Fifth Energy Level	30 ^[3]
– Sixth Energy Level	8 ^[3]
– Seventh Energy Level	2 ^[3]
Radius of atom
– Atomic Radius	2.45 Å ^[1]
– Covalent Radius	1.67 Å ^[1]
Electronegativity	1.3 ^[6]
Ionization energy (kJmol^-1) ^[1]	1st	2nd	3rd	4th	5th	6th	7th
	627.2	–	–	–	–	–	–

Fermium Electronic Configuration (Bohr Model)

Uses of Fermium

Due to its minute production and short half-life, it is used for research purposes only ^[2].

Health Hazards

It is potentially dangerous due to its radioactivity ^[1].

Interesting Facts

Fermium, along with Einsteinium, was one of the first synthetic elements produced after the testing of a hydrogen bomb ^{[10, 15]}.
As the hydrogen bomb testing was top secret, researchers could only publish the discovery of Fm in 1955 after producing it officially in a laboratory ^{[1, 3, 10]}.