Chemistry Class 11 Chapter 9. Hydrogen | Page 2

1 . Hydrogen is the lightest element known since it has an atomic mass of 1.0079
2 . Hydrogen resembles Group 1 elements because it has electronic configuration ( 1s 1 ) similar to alkali metals and can loose one electron to form unipositive ions
3 . Hydrogen also resembles elements of group 17 ( Halogens ) because hydrogen just like halogens needs just one electron to acquire the configuration of the nearest noble gas i . e . Helium
4 . Hydrogen has three isotopes - Protium , deuterium and tritium
Isotopes No . of No . of No . of Mass protons ( p ) neutrons ( n ) electrons ( e ) number
( M )
Protium ( 1H )
Deuterium ( 1 H or D )
Tritium 1 H or D
1 0 1 1
1 1 1 2
1 2 1 3
5 . In elemental form Hydrogen exists as a diatomic molecule H2 and is called dihydrogen
6 . Water gas is name given to the mixture of carbon monoxide and hydrogen . Water gas is also called synthesis gas or syngas
7 . The production of dihydrogen can be increased by reacting carbon monoxide of syngas mixtures with steam in the presence of iron chromate as catalyst . This reaction is called as water gas shift reaction
8 . The process of producing ' syngas ' from coal is called ' coal gasification '
C ( s ) + H2O
1270 K
2 ( g )