Category Archives: Elements

Elements are the smallest units of matter that can’t be divided using chemical means. They are the building blocks of matter. Learn the names of the elements and get facts about them.

Actinium Facts – Atomic Number 89 or Ac

These are vials of glowing actinium-225. Oak Ridge National Laboratory, US Department of Energy

These are vials of glowing actinium-225. Oak Ridge National Laboratory, US Department of Energy

Element Name: Actinium

Symbol: Ac

Atomic Number: 89

Atomic Weight: 227.0278

Electron Configuration: [Rn] 6d1 7s2

Element Classification: Radioactive Rare Earth (Actinide Series)

Discovery: Andre-Louis Debierne 1899 (France)

Word Origin: Greek: akis, aktinos (ray).

Melting Point (K): 1320

Boiling Point (K): 3470

Appearance: heavy, silvery-white metal that is highly radioactive – glows with a pale blue light

Atomic Radius (pm): 188

Atomic Volume (cc/mol): 22.54

Ionic Radius: 118 (+3e)

Fusion Heat (kJ/mol): (10.5)

Evaporation Heat (kJ/mol): (292.9)

Pauling Negativity Number: 1.1

First Ionizing Energy (kJ/mol): 665.5

Oxidation States: 3

Lattice Structure: Face-Centered Cubic

Lattice Constant (Å): 5.310

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange’s Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)

 

Americium Facts – Element 95 or Am

This is a disk of americium-241 viewed under a microscope. Bionerd, Creative Commons License

This is a disk of americium-241 viewed under a microscope. Bionerd, Creative Commons License

Element Name: Americium

Atomic Number: 95

Symbol: Am

Atomic Weight: 243.0614

Electron Configuration: [Rn] 5f7 7s2

Atomic Number: 95

Element Classification: Radioactive Rare Earth Element (Actinide Series)

Discovered By: G.T.Seaborg, R.A.James, L.O.Morgan, A.Ghiorso

Discovery Date: 1945 (United States)

Name Origin: named for the American continent, similar to the naming of the element europium.

Density (g/cc): 13.67

Melting Point (K): 1267

Boiling Point (K): 2880

Appearance: silvery-white, radioactive metal

Atomic Radius (pm): 173

Atomic Volume (cc/mol): 20.8

Ionic Radius: 92 (+4e) 107 (+3e)

Fusion Heat (kJ/mol): (10.0)

Evaporation Heat (kJ/mol): 238.5

Pauling Negativity Number: 1.3

Oxidation States: 6, 5, 4, 3

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange’s Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)

 

Bohrium Facts – Element 107 or Bh

Element 107 - Bohrium

Element 107 – Bohrium

Element Name: Bohrium (formerly Nielsbohrium)

Atomic Number: 107

Symbol: Bh

Atomic Weight: [264]

Discovery: Dubna (Russia) 1975 or Heavy Ion Research Lab (Germany) 1976

Electron Configuration: [Rn] 7s2 5f14 6d5

Word Origin: Formerly Ns, Nielsbohrium. Named in honor of Niels Bohr.

Sources: Bohrium is a man-made element. In 1976, Soviet scientists at Dubna announced they had synthesized element 107 by bombarding Bi-204 with heavy nuclei of Cr-54. There are reports that the element was ‘glimpsed’ for 2/1000 s in 1975. Bohrium was produced by bombarding a rapidly rotating cylinder target, coated with a thin layer of bismuth metal, with a stream of tangentially fired Cr-54 ions. West German physicists at the Heavy Ion Research Laboratory at Darmstadt verified the existence of element 107, creating and identifying six nuclei of Bohrium.

Element Classification: Transition Metal

Appearance: radioactive synthetic metal

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange’s Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)

 

Dysprosium Facts – Element 66 or Dy

Dysprosium is a silver-colored rare earth element. This is a chunk of purified dysprosium metal. Tomihahndorf

Dysprosium is a silver-colored rare earth element. This is a chunk of purified dysprosium metal. Tomihahndorf

Element Name: Dysprosium

Atomic Number: 66

Symbol: Dy

Atomic Weight: 162.50

Discovered By: Paul-Emile Lecoq de Boisbaudran

Discovery Date: 1886 (France)

Electronic Configuration: [Xe] 4f10 6s2

Atomic Weight: 162.50

Element Classification: Rare Earth (Lanthanide Series)

Name Origin: Greek: dysprositos (hard to get at)

Density (g/cc): 8.55

Melting Point (°K): 1685

Boiling Point (°K): 2835

Appearance: soft, lustrous, silvery metal

Atomic Radius (pm): 180

Atomic Volume (cc/mol): 19.0

Covalent Radius (pm): 159

Ionic Radius: 90.8 (+3e)

Specific Heat (@20°C J/g mol): 0.173

Evaporation Heat (kJ/mol): 291

First Ionizing Energy (kJ/mol): 567

Oxidation States: 3

Lattice Structure: Hexagonal

Lattice Constant (Å): 3.590

Lattice C/A Ratio: 1.573

Sources: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange’s Handbook of Chemistry (1952)

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Mendelevium Facts – Element 101 or Md

Mendelevium is a radioactive metal.

Mendelevium is a radioactive metal.

Element Name: Mendelevium

Atomic Number: 101

Symbol: Md

Atomic Weight: 258.1

Discovery: G.T. Seaborg, S.G. Tompson, A. Ghiorso, K. Street Jr. (1955, United States)

Electron Configuration: [Rn] 7s2 5f13

Word Origin: Named in honor of Dmitri Mendeleev, who devised a periodic table of the elements

Isotopes: Fourteen isotopes have been recognized.

Properties: Mendelevium is the ninth transuranium element of the actinide series. Experiments indicate that mendelevium has a moderately stable dipositive (II) oxidation state in addition to the tripositive (III) oxidation state, as is characteristic of the actinide elements.

Uses: Md-256 has been used to determine some of the chemical properties of mendelevium in aqueous solution.

Sources: Mendelevium first was produced during the bombardment of Es-253 with helium ions in the Berkeley 60-inch cyclotron. The isotope produced was Md-256, with a half-life of 76 min. Md-256 was synthesized on a one-atom-at-a-time basis.

Element Classification: Radioactive Rare Earth Element (Actinide Series)

Melting Point (K): 1100

Appearance: Radioactive, synthetic metal

Atomic Radius (pm): 287

Pauling Negativity Number: 1.3

First Ionizing Energy (kJ/mol): (635)

Oxidation States: 3

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange’s Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)

 

Einsteinium Facts – Element 99 or Es

Einsteinium is a man-made radioactive metal. This quartz vial contains approximately 300 micrograms of solid Einsteinium-253. The blue light results from the intense radiation produced by einsteinium, primarily in the form of alpha decay. R.G. Haire, US Department of Energy

Einsteinium is a man-made radioactive metal. This quartz vial contains approximately 300 micrograms of solid Einsteinium-253. The blue light results from the intense radiation produced by einsteinium, primarily in the form of alpha decay. R.G. Haire, US Department of Energy

Element Name: Einsteinium

Atomic Number: 99

Symbol: Es

Atomic Weight: (254)

Discovery: Ghiorso et al. 1952

Electron Configuration: 5f11

Group: Rare Earth, Actinides

Melting Point: 1133.2 K

1st Ionization Energy: 619 kJ/mole

Electronegativity: 1.3

Shells: 2,8,18,32,29,8,2

Characteristics: Radioactive

Atomic Radius: 186 pm

Source: Man-made

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange’s Handbook of Chemistry (1952)

Praseodymium Facts – Element 59 or Pr

This is a chunk of pure praseodymium metal under a protective argon atmosphere. Praseodymium is a soft silvery metal that develops a green oxide coating that spalls off when exposed to air. Tomihahndorf

This is a chunk of pure praseodymium metal under a protective argon atmosphere. Praseodymium is a soft silvery metal that develops a green oxide coating that spalls off when exposed to air. Tomihahndorf

Element Name: Praseodymium

Atomic Number: 59

Symbol: Pr

Atomic Weight: 140.90765

Element Classification: Rare Earth Element (Lanthanide Series)

Discoverer: C.F. Aver von Weisbach

Discovery Date: 1885 (Austria)

Name Origin: Greek: prasios and didymos (green twin); from its green salts

Density (g/cc): 6.773

Melting Point: 1204 K

Boiling Point: 3785 K

Appearance: silvery-white, moderately soft, malleable, ductile metal

Atomic Radius (pm): 182

Atomic Volume (cc/mol): 20.8

Covalent Radius (pm): 165

Ionic Radius: 90 (+4e) 101.3 (+3e)

Specific Heat (@20°C J/g mol): 0.192

Fusion Heat (kJ/mol): 11.3

Evaporation Heat (kJ/mol): 331

Pauling Negativity Number: 1.13

First Ionizing Energy (kJ/mol): 526.6

Oxidation States: 4, 3

Electronic Configuration: [Xe] 4f3 6s2

Lattice Structure: Hexagonal

Lattice Constant (Å): 3.670

Lattice C/A Ratio: 1.614

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange’s Handbook of Chemistry (1952)