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Iridium
Thermal Expansion of Promethium
Se (Symbol of Selenium)
97 (Atomic Number of Berkelium)
Atomic Mass of Phosphorus in lb

La

Lanthanum

Properties

Isotopes

Electrons

39 known isotopes (1 stable, 38 radioactive)

Show stable only

¹¹⁷La

Mass

116.950326 u

Abundance

—

Half-life

23.5 milliseconds

Spin/Parity

(3/2+ 3/2-)

Decay Mode(s)

Proton emission (93.9%), EC/β⁺ (6.1%)

¹²⁰La

Mass

119.938196 u

Abundance

—

Half-life

2.8 seconds

Spin/Parity

—

Decay Mode(s)

EC/β⁺ (100%), ECP (0%)

¹²¹La

Mass

120.933236 u

Abundance

—

Half-life

5.3 seconds

Spin/Parity

—

Decay Mode(s)

EC/β⁺ (100%)

¹²²La

Mass

121.930710 u

Abundance

—

Half-life

8.6 seconds

Spin/Parity

—

Decay Mode(s)

EC/β⁺ (100%)

¹²³La

Mass

122.926300 u

Abundance

—

Half-life

16.3 seconds

Spin/Parity

—

Decay Mode(s)

EC/β⁺ (100%)

¹²⁴La

Mass

123.924574 u

Abundance

—

Half-life

21 seconds

Spin/Parity

—

Decay Mode(s)

EC/β⁺ (100%)

¹²⁵La

Mass

124.920816 u

Abundance

—

Half-life

64.8 seconds

Spin/Parity

(3/2+)

Decay Mode(s)

EC/β⁺ (100%)

¹²⁶La

Mass

125.919513 u

Abundance

—

Half-life

54 seconds

Spin/Parity

(4 5)

Decay Mode(s)

EC/β⁺ (0%)

¹²⁷La

Mass

126.916375 u

Abundance

—

Half-life

5.1 m

Spin/Parity

(11/2-)

Decay Mode(s)

EC/β⁺ (100%)

¹²⁸La

Mass

127.915592 u

Abundance

—

Half-life

5.18 m

Spin/Parity

(5+)

Decay Mode(s)

Electron capture (100%)

¹²⁹La

Mass

128.912696 u

Abundance

—

Half-life

11.6 m

Spin/Parity

(3/2+)

Decay Mode(s)

EC/β⁺ (100%)

¹³⁰La

Mass

129.912369 u

Abundance

—

Half-life

8.7 m

Spin/Parity

3(+)

Decay Mode(s)

EC/β⁺ (100%)

¹³¹La

Mass

130.910070 u

Abundance

—

Half-life

59 m

Spin/Parity

3/2+

Decay Mode(s)

EC/β⁺ (100%)

¹³²La

Mass

131.910119 u

Abundance

—

Half-life

4.8 h

Spin/Parity

Decay Mode(s)

EC/β⁺ (100%)

¹³³La

Mass

132.908218 u

Abundance

—

Half-life

3.912 h

Spin/Parity

5/2+

Decay Mode(s)

EC/β⁺ (100%)

¹³⁴La

Mass

133.908514 u

Abundance

—

Half-life

6.45 m

Spin/Parity

Decay Mode(s)

EC/β⁺ (100%)

¹³⁵La

Mass

134.906984 u

Abundance

—

Half-life

19.5 h

Spin/Parity

5/2+

Decay Mode(s)

EC/β⁺ (100%)

¹³⁶La

Mass

135.907635 u

Abundance

—

Half-life

9.87 m

Spin/Parity

Decay Mode(s)

EC/β⁺ (100%)

¹³⁷La

Mass

136.906450 u

Abundance

—

Half-life

6E+4 years

Spin/Parity

7/2+

Decay Mode(s)

Electron capture (100%)

¹³⁸La

Mass

137.907124 u

Abundance

0.0888%

Half-life

1.03E+11 years

Spin/Parity

Decay Mode(s)

EC/β⁺ (65.5%), β⁻ (34.5%)

¹³⁹La Stable

Mass

138.906363 u

Abundance

99.9112%

Half-life

Stable

Spin/Parity

7/2+

Decay Mode(s)

—

¹⁴⁰La

Mass

139.909487 u

Abundance

—

Half-life

1.67858 d

Spin/Parity

Decay Mode(s)

β⁻ (100%)

¹⁴¹La

Mass

140.910971 u

Abundance

—

Half-life

3.92 h

Spin/Parity

7/2(+)

Decay Mode(s)

β⁻ (100%)

¹⁴²La

Mass

141.914091 u

Abundance

—

Half-life

91.1 m

Spin/Parity

Decay Mode(s)

β⁻ (100%)

¹⁴³La

Mass

142.916079 u

Abundance

—

Half-life

14.2 m

Spin/Parity

(7/2)+

Decay Mode(s)

β⁻ (100%)

¹⁴⁴La

Mass

143.919646 u

Abundance

—

Half-life

40.8 seconds

Spin/Parity

(3-)

Decay Mode(s)

β⁻ (100%)

¹⁴⁵La

Mass

144.921808 u

Abundance

—

Half-life

24.8 seconds

Spin/Parity

(5/2+)

Decay Mode(s)

β⁻ (100%)

¹⁴⁶La

Mass

145.925688 u

Abundance

—

Half-life

6.1 seconds

Spin/Parity

(2-)

Decay Mode(s)

β⁻ (100%), β⁻n (0.007%)

¹⁴⁷La

Mass

146.928418 u

Abundance

—

Half-life

4.06 seconds

Spin/Parity

(5/2+)

Decay Mode(s)

β⁻ (100%), β⁻n (0.041%)

¹⁴⁸La

Mass

147.932679 u

Abundance

—

Half-life

1.26 seconds

Spin/Parity

(2-)

Decay Mode(s)

β⁻ (100%), β⁻n (0.15%)

¹⁴⁹La

Mass

148.935351 u

Abundance

—

Half-life

1.091 seconds

Spin/Parity

(3/2)

Decay Mode(s)

β⁻ (100%), β⁻n (1.41%)

¹⁵⁰La

Mass

149.939548 u

Abundance

—

Half-life

0.59 seconds

Spin/Parity

(3+)

Decay Mode(s)

β⁻ (100%), β⁻n (2.7%)

¹⁵¹La

Mass

150.942769 u

Abundance

—

Half-life

0.457 seconds

Spin/Parity

(1/2+)

Decay Mode(s)

β⁻ (100%)

¹⁵²La

Mass

151.947085 u

Abundance

—

Half-life

0.298 seconds

Spin/Parity

(2-)

Decay Mode(s)

β⁻ (100%)

¹⁵³La

Mass

152.950553 u

Abundance

—

Half-life

0.245 seconds

Spin/Parity

—

Decay Mode(s)

β⁻ (100%)

¹⁵⁴La

Mass

153.955416 u

Abundance

—

Half-life

0.161 seconds

Spin/Parity

(2-)

Decay Mode(s)

β⁻ (100%)

¹⁵⁵La

Mass

154.959280 u

Abundance

—

Half-life

101 milliseconds

Spin/Parity

—

Decay Mode(s)

β⁻ (100%)

¹⁵⁶La

Mass

155.964519 u

Abundance

—

Half-life

84 milliseconds

Spin/Parity

(4+)

Decay Mode(s)

β⁻ (100%)

¹⁵⁷La

Mass

156.968792 u

Abundance

—

Half-life

Unknown

Spin/Parity

—

Decay Mode(s)

β⁻ (100%)

Decay mode abbreviations:

β⁻ = Beta minus decay, β⁺ = Beta plus decay, EC = Electron capture, α = Alpha decay

n = Neutron emission, p = Proton emission, SF = Spontaneous fission, IT = Isomeric transition

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