 − 3 × 1018 years , giving about 1 alpha decay per two minutes in every kilogram of natural europium . This value is in reasonable agreement with theoretical predictions . Besides the natural radioisotope 151Eu , 35 artificial radioisotopes have been characterized , the most stable being 150Eu with a half @-@ life of 36 @.@ 9 years , 152Eu with a half @-@ life of 13 @.@ 516 years , and 154Eu with a half @-@ life of 8 @.@ 593 years . All the remaining radioactive isotopes have half @-@ lives shorter than 4 @.@ 7612 years , and the majority of these have half @-@ lives shorter than 12 @.@ 2 seconds . This element also has 8 meta states , with the most stable being 150mEu ( t1 / 2 = 12 @.@ 8 hours ) , 152m1Eu ( t1 / 2 = 9 @.@ 3116 hours ) and 152m2Eu ( t1 / 2 = 96 minutes ) . 
 − 3 × 1018 years , giving about 1 alpha decay per two minutes in every kilogram of natural europium . This value is in reasonable agreement with theoretical predictions . Besides the natural radioisotope 151Eu , 35 artificial radioisotopes <a href='been_done' title='1'><mark>have</mark></a> been characterized , the most stable being 150Eu with a half @-@ life of 36 @.@ 9 years , 152Eu with a half @-@ life of 13 @.@ 516 years , and 154Eu with a half @-@ life of 8 @.@ 593 years . All the remaining radioactive isotopes <a href='got' title='2'><mark>have</mark></a> half @-@ lives shorter than 4 @.@ 7612 years , and the majority of these <a href='got' title='3'><mark>have</mark></a> half @-@ lives shorter than 12 @.@ 2 seconds . This element also <a href='got' title='4'><mark>has</mark></a> 8 meta states , with the most stable being 150mEu ( t1 / 2 = 12 @.@ 8 hours ) , 152m1Eu ( t1 / 2 = 9 @.@ 3116 hours ) and 152m2Eu ( t1 / 2 = 96 minutes ) . 
− 3 × 1018 years , giving about 1 alpha decay per 2 minutes in every kilogram of natural europium . This value is in reasonable agreement with theoretical predictions . Besides da natural radioisotope 151Eu , 35 artificial radioisotopes done been characterized , the most stable being 150Eu with a half @-@ life of 36 @.@ 9 yrs , 152Eu with a half @-@ life of 13 @.@ 516 years , and 154Eu with a half @-@ life of 8 @.@ 593 years . All the remaining radioactive isotopes got half @-@ lives shorter den 4 @.@ 7612 years , and the majority of dese got half @-@ lives shorter tden12 @.@ 2 seconds . This element also got 8 meta states , with tdamost stable bein 150mEu ( t1 / 2 = 12 @.@ 8 hrs ) , 152m1Eu ( t1 / 2 = 9 @.@ 3116 hours ) and 152m2Eu ( t1 / 2 = 96 minutes ) .