Some properties of the nitrogen group elements

nitrogen phosphorus (white)

atomic number 7 15

atomic weight 14.0067 30.9738

colour of element colourless white

melting point (&\\#x00b0;C) −209.86 44.1

boiling point (&\\#x00b0;C) −195.8 280

density at 25 &\\#x00b0;C

(grams per cubic centimetre) 1.25 (grams per litre) 1.82

solubility in water

(volume per volume of water) 0.0231 none

valence 3, (5) 3, 5

isotopic abundance (terrestrial, percent) nitrogen-14 (99.63), nitrogen-15 (0.37) phosphorus-31 (100)

radioactive isotopes (mass numbers) 12, 13, 16, 17 28–30, 32–34

heat of fusion (calories per gram) 6.1 5.03

heat of vaporization (calories per gram) 47.7 130

specific heat (calories per gram per &\\#x00b0;C) 0.249 (diatomic) 0.189

critical temperature (&\\#x00b0;C) −147.1 675

critical pressure (atm) 33.5 80

electrical resistivity (microhm-centimetres) — 1 × 10¹⁷

hardness (Mohs' scale) — 0.5

crystal structure at 20 &\\#x00b0;C — cubic

radius

covalent (angstroms) 0.74 1.10

ionic (+3 ion, angstroms) 0.16 0.44

ionization energy (first, kilocalories per mole) 337 255

electronegativity

(Pauling) 3.05 2.15

(Sanderson) 4.49 3.34

arsenic antimony bismuth

atomic number 33 51 83

atomic weight 74.9216 121.75 208.980

colour of element steel gray silver pinkish silver

melting point (&\\#x00b0;C) 817 (28 atm) 630.5 271.3

boiling point (&\\#x00b0;C) 613 (sublimes) 1,380 1,560

density at 25 &\\#x00b0;C

(grams per cubic centimetre) 5.73 6.684 9.8

solubility in water

(volume per volume of water) none none none

valence 3, 5 3, 5 3, 5

isotopic abundance (terrestrial, percent) arsenic-75 (100) antimony-121 (57.25), antimony-123 (42.75) bismuth-209 (100)

radioactive isotopes (mass numbers) 68–74, 76–81, 85 112–120, 122, 124–135 196, 199–208, 210–215

heat of fusion (calories per gram) 88.5 38.3 12.5

heat of vaporization (calories per gram) 102 161 204.3

specific heat (calories per gram per &\\#x00b0;C) 0.082 0.0494 0.0294

critical temperature (&\\#x00b0;C) — — —

critical pressure (atm) — — —

electrical resistivity (microhm-centimetres) 33.3 (20 &\\#x00b0;C) 39 (0 &\\#x00b0;C) 106.8 (0 &\\#x00b0;C)

hardness (Mohs' scale) 3.5 3.0–3.5 2.5

crystal structure at 20 &\\#x00b0;C hexagonal hexagonal hexagonal

radius

covalent (angstroms) 1.19 1.38 1.46

ionic (+3 ion, angstroms) 0.58 0.76 0.96

ionization energy (first, kilocalories per mole) 228 201 170

electronegativity

(Pauling) 2.10 2.05 1.8

(Sanderson) 3.91 3.37 3.16