hydrogen

Symbol: H
Atomic number: 1
Atomic weight: 1.00794
Group: 1
Group name: (none). While normally shown at the top of the Group 1 elements in the periodic table, the term "alkaline metal" refers only to Group 1 elements from lithium onwards.
Period: 1
Block: s
CAS ID: 1333-74-0
Shell structure: 1
Electron configuration: 1s1
State: |standardstate|
Melting point: 14.01 [or -259.14 °C (-434.45 °F)]
Boiling point: 20.28 [or -252.87 °C (-423.17 °F)]
Ionization energy/kJ per mol: 1312.0
Common oxidation states: 1, and -1
Pauling electronegativity: 2.20