| colspan=2 style="text-align: center" | Main article: Isotopes of रेडियम
रेडियम
88Ra
Ba

Ra

Ubn
फ्रान्सियमरेडियमएक्टिनियम
रुप
silvery white metallic
साधारण गुण
नां, चिं, ल्या रेडियम, Ra, 88
उच्चारण /ˈrdiəm/
RAY-dee-əm
धातुया वर्ग alkaline earth metal
ग्रुप, पिरियद, ब्लक 27, s
Standard atomic weight (226)
Electron configuration [Rn] 7s2
2, 8, 18, 32, 18, 8, 2
History
Discovery पियरे क्युरीमेरी क्युरी (1898)
First isolation मेरी क्युरी (1902)
Physical properties
Phase solid
Density (near r.t.) 5.5 g·cm−3
Melting point 973 K, 700 °C, 1292 °F
Boiling point 2010 K, 1737 °C, 3158.6 °F
Heat of fusion 8.5 kJ·mol−1
Heat of vaporization 113 kJ·mol−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 819 906 1037 1209 1446 1799
Atomic properties
Oxidation states 2 (strongly basic oxide)
Electronegativity 0.9 (Pauling scale)
Ionization energies 1st: 509.3 kJ·mol−1
2nd: 979.0 kJ·mol−1
Covalent radius 221±2 pm
Van der Waals radius 283 pm
Miscellanea
Crystal structure body-centered cubic
रेडियम has a body-centered cubic crystal structure
Magnetic ordering nonmagnetic
Electrical resistivity (20 °C) 1 µΩ·m
Thermal conductivity 18.6 W·m−1·K−1
CAS registry number 7440-14-4
Most stable isotopes
iso NA half-life DM DE (MeV) DP
223Ra trace 11.43 d α 5.99 219Rn
224Ra trace 3.6319 d α 5.789 220Rn
226Ra trace 1601 y α 4.871 222Rn
228Ra trace 5.75 y β 0.046 228Ac
· r

References