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Compare Magnesium vs Phosphorus

Comparing Magnesium (Mg) and Phosphorus (P). Atomic numbers 12 and 15 with atomic masses 24.304 u and 30.974 u, classified as alkaline earth metal and nonmetal. Below: a side-by-side comparison of their physical, atomic, electron-configuration and historical properties, including density, melting and boiling points, ionization energies, oxidation states and discovery history.

vs
Mg
Magnesium
#12
P
Phosphorus
#15

Periodic properties of the elements

MagnesiumPhosphorus
SymbolMgP
Atomic number1215
Group215
Period33
Blocksp
Element categoryAlkaline Earth MetalNonmetal

Physical properties

MagnesiumPhosphorus
Phase at STPSolidSolid
Density1.738 g/cm31.823 g/cm3
Atomic weight24.304 u30.9738 u
Melting point923 K
649.85 °C
1201.73 °F		-
Boiling point1363 K
1089.85 °C
1993.73 °F		-

Atomic properties

MagnesiumPhosphorus
Electronegativity (Pauling Scale)1.312.19
Electron affinity-40 kJ/mol72.037 kJ/mol
Oxidation states+1, +2
(a strongly basic oxide)		−3, −2, −1, 0, +1, +2, +3, +4, +5
(a mildly acidic oxide)
Ionization energies
  1. 737.7 kJ/mol
  2. 1450.7 kJ/mol
  3. 7732.7 kJ/mol
  4. 10542.5 kJ/mol
  5. 13630 kJ/mol
  6. 18020 kJ/mol
  7. 21711 kJ/mol
  8. 25661 kJ/mol
  9. 31653 kJ/mol
  10. 35458 kJ/mol
  11. 169988 kJ/mol
  12. 189368 kJ/mol
  1. 1011.8 kJ/mol
  2. 1907 kJ/mol
  3. 2914.1 kJ/mol
  4. 4963.6 kJ/mol
  5. 6273.9 kJ/mol
  6. 21267 kJ/mol
  7. 25431 kJ/mol
  8. 29872 kJ/mol
  9. 35905 kJ/mol
  10. 40950 kJ/mol
  11. 46261 kJ/mol
  12. 54110 kJ/mol
  13. 59024 kJ/mol
  14. 271791 kJ/mol
  15. 296195 kJ/mol

Electron configuration

MagnesiumPhosphorus
Shorthand configuration[Ne] 3s2 [Ne] 3s2 3p3
Full configuration1s2 2s2 2p6 3s2 1s2 2s2 2p6 3s2 3p3
Electrons per shell2, 8, 22, 8, 5

History

MagnesiumPhosphorus
DiscoveryJoseph Black (1755)Hennig Brand (1669)
First isolationHumphry Davy (1808)Hennig Brand (1669)
Named byHumphry Davy (1812)
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