H is the symbol of hydrogen and its atomic number is: 1
it belong in the periodic table to the first group, first row and block s
it is a part of the nonmetals family such as carbon , oxygen...
it was discovered in 1766 by the british physicist and chemist henry cavendish
hydrogen as name comes from the greek word hydor gennan which means the product of water
Atomic number (Z) 1
Group, block group 1, s-block
Period: period 1
Element category: diatomic nonmetal, could be considered metalloid
Standard atomic weight (Ar) 1.008 (1.00784–1.00811).
Electron configuration: 1s1
per shell: 1
Physical properties
Color: colorless
Phase: gas
Melting point: 13.99 K (−259.16 °C, −434.49 °F)
Boiling point: 20.271 K (−252.879 °C, −423.182 °F)
Density at stp (0 °C and 101.325 kPa) 0.08988 g/L
when liquid, at m.p. 0.07 g/cm3 (solid: 0.0763 g·cm−3)[4]
when liquid, at b.p. 0.07099 g/cm3
Triple point: 13.8033 K, 7.041 kPa
Critical point: 32.938 K, 1.2858 MPa
Heat of fusion (H2) 0.117 kJ/mol
Heat of vaporization: (H2) 0.904 kJ/mol
Molar heat capacity (H2) 28.836 J/(mol·K)
Atomic properties
Oxidation states: −1, +1 (an amphoteric oxide)
Electronegativity: Pauling scale: 2.20
Ionization energies 1st: 1312.0 kJ/mol
Covalent radius: 31±5 pm
Van der Waals radius: 120 pm
Crystal structure: hexagonal Hexagonal crystal
Speed of sound: 1310 m/s (gas, 27 °C)
Thermal conductivity: 0.1805 W/(m·K)
Magnetic ordering diamagnetic.
CAS Number 1333-74-0