GADOLINIUM

Atomic symbol: Gd Atomic weight: 157.25

Atomic number: 64

Electron configuration: 2-8-18-25-9-2

Oxidation states: +3, +4 State of matter: solid Heavy metal, brittle

Discovered in 1880 by J.C.G de Marignac and P.É Lecoq de Boisbaudran

Boils at 3223°C, melts at 1311°C

Notes:

Gadolinium has a silvery-white color and is moderately ductile. It becomes ferromagnetic below 17°C, and near absolute zero, becomes superconducting. It is used for some electronics, high-temperature refractories, and as an alloying agent.

GALLIUM

Atomic symbol: Ga Atomic weight: 69.723

Atomic number: 31

Electron configuration: 2-8-18-3

Oxidation states: +3 State of matter: solid Heavy metal, low melting

Discovered in 1875 by Paul-Émile Lecoq de Boisbaudran

Boils at 2403°C, melts at 29.78°C

Notes:

Gallium liquefies just above room temperature. It is silvery white, and soft enough to be cut with a knife. It may take on a bluish tinge due to superficial oxidation. Gallium expands when solidified and super-cools readily, sustaining its liquid form as low as 0°C. It can be used as a coating for optical mirrors, as a liquid seal in a strongly heated apparatus, and as a substitute for mercury in ultraviolet lamps.

GERMANIUM

Atomic symbol: Ge Atomic weight: 72.64

Atomic number: 32

Electron configuration: 2-8-18-4

Oxidation states: +2, +4 State of matter: solid Heavy metal, low melting

Discovered in 1886 by Clements Winkler Boils at 2830°C, melts at 937.4°C

Notes:

Germanium is an important element used in the manufacture of transistors and photocells. Germanium is never found free and is quite brittle, even though the atoms of a germanium crystal are found in the same arrangement as carbon atoms in a diamond. It also reacts quickly with the halogens to form tetrahalides.

GOLD

Atomic symbol: Au

Atomic weight: 196.966569

Atomic number: 79

Electron configuration: 2-8-18-32-18-1

Oxidation states: +1, +3

State of matter: solid Heavy metal, ductile Discovered in ancient times

Boils at 2966°C, melts at 1063°C

Notes:

Gold is dense, precious, and has a bright yellow color. It is a good conductor of heat and electricity and is soft and very malleable and ductile. It is the most malleable metal known to man. An ounce of gold can be pounded into a sheet of 300 square feet. In thin sheets it transmits a green light, and it is often used in printed circuits and semiconductors.

HAFNIUM

Atomic symbol: Hf Atomic weight: 178.49

Atomic number: 72

Electron configuration: 2-8-18-32-10-2

Oxidation states: +4

State of matter: solid

Heavy metal, ductile

Discovered in 1923 by Dirk Coster and George Charles de Hevesy

Boils at 5400°C, melts at 2150°C

Notes:

Hafnium is a highly lustrous ductile metal of hexagonal crystal structure. Chemically similar to zirconium and thorium, hafnium is used as nuclear control rods.

HELIUM

Atomic symbol: He Atomic weight: 4.002602

Atomic number: 2

Electron configuration: 2

Oxidation states: 0

State of matter: gas

Noble gas element

Discovered in 1895 by Sir William Ramsay Boils at -268.9°C, melts at -272.2°C

Notes:

Helium is a colorless, odorless, tasteless, nonflammable, monatomic inert gas. It is obtained from natural gas deposits by liquefying all other constituents and collecting the helium. The percentage obtained from these deposits may range from 1% to 2%. It is sometimes used to fill balloons and airships, along with many other scientific applications.

HOLMIUM

Atomic symbol: Ho Atomic weight: 164.93032

Atomic number: 67

Electron configuration: 2-8-18-29-8-2

Oxidation states: +3

State of matter: solid

Heavy metal, brittle

Discovered in 1878 by J.L Soret and M. Delafontaine

Boils at 2720°C, melts at 140°C

Notes:

Holmium is a rare earth metal of the yttrium group and a member of the lanthanide series. It is silver in color made of hexagonal close packed crystals. It is one of the most paramagnetic sources known.

HYDROGEN

Atomic symbol: H Atomic weight: 1.00794

Atomic number: 1

Electron configuration: 1

Oxidation states: ±1

State of matter: gas

Alkali metal

Discovered in 1790 by Henry Cavendish Boils at -252.8°C, melts at -259.14°C

Notes:

Hydrogen is a colorless, odorless, tasteless gas that can be flammable or explosive when mixed with air, oxygen, and chlorine. Hydrogen is not very reactive at room temperature, but at higher temperatures it burns vigorously and often explosively in air or oxygen to form water. In the presence of a catalyst and under pressure, hydrogen will combine with vegetable oils to form solid fats used as shortening, in a process known as hydrogenation. This process is extensively used in the refining of oil products to increase the yields of gasoline. It is also commonly used to make ammonia and many other chemical substances. Other uses are to fuel rockets and in fuel cells to generate electricity.

INDIUM

Atomic symbol: In Atomic weight: 114.818

Atomic number: 49

Electron configuration: 2-8-18-18-3

Oxidation states: +3

State of matter: solid

Heavy metal, low melting

Discovered in 1863 by Ferdinand Reich and Theodor Richter

Boils at 2080°C, melts at 156.61°C

Notes:

Indium is about as rare as silver. It is a soft, white metal with bluish tinge. Like tin, it emits a screeching sound when bent. It is used in bearing alloys, as a thin film on moving surfaces made from other metals, in dental alloys, and in semiconductor research.

IODINE

Atomic symbol: I

Atomic weight: 126.90447

Atomic number: 53

Electron configuration: 2-8-18-18-7

Oxidation states: ±1, +5, 7

State of matter: solid

Non-metal

Discovered in 1811 by Bernard Courtois Boils at 184°C, melts at 113.5°C

Notes:

Iodine is bluish-black in color with a metallic luster, characteristic odor, and sharp acrid taste. At room temperature, iodine sublimes into a violet vapor that irritates the eyes, nose, and throat. It dissolves in alcohol and partially in water to make a brown colored solution.

IRIDIUM

Atomic symbol: Ir

Atomic weight: 192.217

Atomic number: 77

Electron configuration: 2-8-18-32-15-2

Oxidation states: +3, +4

State of matter: solid

Heavy metal, ductile

Discovered in 1804 by Smithson Tennant Boils at 4527°C, melts at 2410°C

Notes:

Very dense and rare, iridium is silvery white in color. It’s main use is in the form of platinum alloys.

IRON

Atomic symbol: Fe Atomic weight: 55.845

Atomic number: 26

Electron configuration: 2-8-14-2

Oxidation states: +2, +3

State of matter: solid

Heavy metal, ductile

Discovered in ancient times

Boils at 3000°C, melts at 1535°C

Notes:

Iron is a soft, ductile, malleable silver metal. It is somewhat magnetic, only holding its magnetism after hardening. Its main ores are hematite, magnetite, and pyrites. Iron can be used as a nutritional supplement, and can be alloyed with other elements to make steels.

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