Atomic symbol: Os

Atomic weight: 190.23

Atomic number: 76

Electron configuration: 2-8-18-32-14-2

Oxidation states: +3, +4

State of matter: solid

Heavy metal, ductile

Discovered in 1804 by Smithson Tennant

Boils at 5000°C, melts at 3000°C


Osmium is a bluish white lustrous metal that is hard and brittle. It was believed to be the densest element; however, data shows it is slightly less dense than iridium.


Atomic symbol: Pd Atomic weight: 106.42

Atomic number: 46

Electron configuration: 2-8-18-18-0

Oxidation states: +2, +4

State of matter: solid

Heavy metal, ductile

Discovered in 1803 by William Hyde Wollaston

Boils at 2927°C, melts at 1552°C


Palladium is a silver, white metal that also occurs as a black powder and as spongy masses that can be compressed to a compact mass. It is extremely ductile and often used as a catalyst. Small amounts of palladium alloyed with gold produces the best white gold. Its chief use is for electrical contacts on telephone equipment.


Atomic symbol: P

Atomic weight: 30.973762

Atomic number: 15

Electron configuration: 2-8-5

Oxidation states: ±3, +5

State of matter: solid Non-metal

Discovered in 1669 by Hennig Brand

Boils at 280°C, melts at 44.1°C


Phosphorus exists in three main allotropic forms—white, black, and red. It is too active to be found in nature, and most of it is combined with oxygen. Its principal ores are phosphorite and apatite. White phosphorous is waxy, soft and translucent, and becomes brittle at 5.5°C. It is crystalline, insoluble in water, and extremely poisonous.


Atomic symbol: Pt Atomic weight: 195.084

Atomic number: 78

Electron configuration: 2-8-18-32-16-2

Oxidation states: +2, +4

State of matter: solid

Heavy metal, ductile

Discovered in 1554 by Julius Caesar Scalinger

Boils at 3827°C, melts at 1769°C


Platinum is a silver-gray, lustrous, malleable and ductile metal. It is very heavy and very precious. It also has good resistance to corrosion and chemical attack. It is used as crucibles, electrodes, and dishes in the lab for heating up materials.


Atomic symbol: K Atomic weight: 39.0983

Atomic number: 19

Electron configuration: 2-8-8-1

Oxidation states: +2, +4

State of matter: solid

Light metal

Discovered in 1807 by Sir Humphry Davy

Boils at 760°C, melts at 63.3°C


Potassium is a soft, silvery-white alkali metal that is brittle at low temperatures and tarnishes when exposed to air. It is a major essential element for plant growth, and extremely reactive. Potassium is an excellent conductor of heat and electricity. When sufficiently heated, it emits a violet color and bursts into flame when in contact with water. Alloyed with sodium it forms an important heat transfer medium in nuclear power plants.

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