Abundance: 0.000137% 
Stable with 1 neutron 
Extraplanetary material, such as lunar and asteroid regolith, have trace amounts of helium-3 from being bombarded by solar winds. The Moon's surface contains helium-3 at concentrations on the order of 0.01 ppm.[ 
4He [2 neutrons] 
Abundance: 99.999863% 
Stable with 2 neutrons 
Liquid helium-4 can be cooled to about 1 kelvin using evaporative cooling. 
5He [3 neutrons] 
Abundance: 
Half life: 7.00(30) x 10-24 seconds 
Decays to 4He. 
Highly unstable, decays to 4He. 
6He [4 neutrons] 
Abundance: 
Half life: 806.7(15) ms [ beta- ] 
Decays to 6Li. 
Produced from 7He or 11Li. 
7He [5 neutrons] 
Abundance: 
Half life: 2.9(5)-21 seconds 
Highly unstable, decays to 6He. 
8He [6 neutrons] 
Abundance: 
Half life: 119.0(15) ms 
Produced from 9He, decomposes to 7Li through beta decay then emits a delayed neutron. 
9He [7 neutrons] 
Abundance: 
Half life: 7(4) x 10-21 seconds 
Highly unstable, decays to 8He. 
10He [8 neutrons] 
Abundance: 
Half life: 2.7(18) x 10-21 seconds 
Highly unstable, decays to 9He. 
ହିଲିୟମ ପରମାଣୁ
ବୈଜ୍ଞାନିକ ଆବିଷ୍କାର
ଧର୍ମ
ସମସ୍ଥାନିକ