Periodic Table/Radium/²²¹Ra

← 220Ra222Ra →

²²¹Ra

Radium-221

Radioactive· Half-life: 25.0 s

Nuclear Propertiesbinding energy · spin-parity · abundance

Protons (Z)

88

Neutrons (N)

133

Mass Number (A)

221

Atomic Mass

221.013917AMU

Spin / Parity

5/2-

Binding E/A

7.498keV

Natural Abundance

Trace / None

Half-life

25.0 s

Decay Modesoverview · half-life · α · β⁻ · β⁺

α

100.0%

¹⁴C

1.2%

Decay Chain

²²¹RaRadium25.0 s

α100.0%

¹⁴C²⁰⁷Pb1.20%

²¹⁷RnRadon593 μs

α100.0%

²¹³PoPolonium3.71 μs

α100.0%

²⁰⁹PbLead3.23 h

β⁻100.0%

²⁰⁹BiBismuth20100000000 Gy

α100.0%

²⁰⁵TlThalliumSTABLE

6-step decay chain → stable · Primary path shown · branching ratios indicated

Other Isotopes of Radium

201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235

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