Page 14 - Curriculum Visions Dynamic Book

Hs see Hassium Hydrogen (H)
Element 1. Hydrogen is the most common element in the universe. It has properties similar to those elements in groups 1 and 7, but it has been assigned to group 1 in the Periodic Table.
Hydrogen accounts for about 87% of all matter in the universe. It is the lightest gas known. Because it is so light, hydrogen is rare in the Earth’s atmosphere. Hydrogen is, however, abundant in compounds – for example, it makes up just over a tenth of the mass of sea water.
Hydrogen is a colourless, odourless, tasteless and flammable gas. It is the simplest of all elements, having just one proton in its nucleus and one electron.
Hydrogen is easily made in
the laboratory by reacting an acid with a metal.The gas given off is hydrogen. Hydrogen is produced commercially by reacting superheated steam with coke.
The isotope known as heavy water is deuterium (2H, or D). Another isotope, tritium, is radioactive. It is used in the production of a hydrogen bomb.
 Hydrogen is the most abundant element in the universe. It is the fuel that burns in a star, creating helium and producing temperatures of 10,000,000°C.
Key facts...
Name: hydrogen
Symbol: H
Atomic number: 1
Atomic weight: 1.01
Position in Periodic Table: group 1 (1); period 1 State at room temperature: gas
Colour: colourless
Density of gas at 20°C: 0.083 g/l
Melting point: –259°C
Boiling point: –253°C
Origin of name: from the Greek words hydro
(water) and gen (to make), meaning maker of
water
Shell pattern of electrons: 1
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