Element	Atomic number	Stable isotopes	% Natural abundance
Helium (He)	2	^3He	0.000137
		^4He	99.999863
Neon (Ne)	10	^20Ne	90.48
		^21Ne	0.27
		^22Ne	9.25
Argon (Ar)	18	^36Ar	0.3365
		^38Ar	0.0632
		^40Ar	99.6003
Krypton (Kr)	36	^78Kr	0.35
		^80Kr	2.28
		^82Kr	11.58
		^83Kr	11.49
		^84Kr	57.00
		^86Kr	17.30
Xenon (Xe)	54	^124Xe	0.09
		^126Xe	0.09
		^128Xe	1.92
		^129Xe	26.44
		^130Xe	4.08
		^131Xe	21.18
		^132Xe	26.89
		^134Xe	10.44
		^136Xe	8.87