Property Oxygen Sulfur Selenium Tellurium Polonium atomic symbol O S Se Te Po atomic number 8 16 34 52 84 atomic mass 16.00 32.07 78.96 127.60 209 (amu) valence electron 2s22p4 3s23p4 4s24p4 5s25p4 6s26p4 configuration* melting point/boiling 115/445 221/685 450/988 254/962 −219/−183 point (°C) density (g/cm3) (g/L) 2.07 4.81 6.24 9.20 1.31 at 25°C atomic radius 48 88 103 123 135 (pm) first ionization 1314 1000 941 869 812 energy (kJ/mol) normal +6, +4, +6, +4, oxidation +6, +4, +2 (+4) −2 −2 −2 −2 state(s) 184 radius 198 (−2), 221 (−2), 230 (−2), 140 (−2) (−2), 29 (pm)† 42 (+6) 56 (+6) 97 (+4) (+6) electron affinity −141 −200 −195 −190 −180 (kJ/mol) electronegativity 3.4 2.6 2.6 2.1 2.0 standard reduction potential (E°, V) +1.23 +0.14 −0.40 −0.79 −1.00 (E0 H2E in → acidic solution) product of SO2 SeO2 TeO2 PoO2 — reaction with O2 type of oxide acidic acidic amphoteric basic — product of NO, NO2 none none none none reaction with N2
Property Oxygen Sulfur Selenium Tellurium Polonium atomic symbol O S Se Te Po atomic number 8 16 34 52 84 atomic mass (amu) 16.00 32.07 78.96 127.60 209 valence electron configuration* 2s22p4 3s23p4 4s24p4 5s25p4 6s26p4 melting point/boiling point (°C) −219/−183 115/445 221/685 450/988 254/962 density (g/cm3) at 25°C 1.31 (g/L) 2.07 4.81 6.24 9.20 atomic radius (pm) 48 88 103 123 135 first ionization energy (kJ/mol) 1314 1000 941 869 812 normal oxidation state(s) −2 +6, +4, −2 +6, +4, −2 +6, +4, −2 +2 (+4) radius (pm)† 140 (−2) 184 (−2), 29 (+6) 198 (−2), 42 (+6) 221 (−2), 56 (+6) 230 (−2), 97 (+4) electron affinity (kJ/mol) −141 −200 −195 −190 −180 electronegativity 3.4 2.6 2.6 2.1 2.0 standard reduction potential (E°, V) (E0 → H2E in acidic solution) +1.23 +0.14 −0.40 −0.79 −1.00 product of reaction with O2 — SO2 SeO2 TeO2 PoO2 type of oxide — acidic acidic amphoteric basic product of reaction with N2 NO, NO2 none none none none
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