#	Element	% of Weight	Weight of element in pounds	Mass of element in a 70-kg person	Atomic Number		#	Element	Mass of element in a 70-kg person	Atomic Number		#	Element	Mass of element in a 70-kg person	Atomic Number
1	oxygen	61.29%	94.6	43 kg	8		21	aluminum	60 mg	13		41	silver	2 mg	47
2	carbon	22.79%	35.2	16 kg	6		22	cadmium	50 mg	48		42	niobium	1.5 mg	41
3	hydrogen	10.00%	15.4	7 kg	1		23	cerium	40 mg	58		43	zirconium	1 mg	40
4	nitrogen	2.57%	4.0	1.8 kg	7		24	barium	22 mg	56		44	lanthanium	0.8 mg	57
5	calcium	1.43%	2.2	1.0 kg	20		25	iodine	20 mg	53		45	gallium	0.7 mg	31
6	phosphorus	1.11%	1.7	780 g	15		26	tin	20 mg	50		46	tellurium	0.7 mg	52
7	potassium	0.20%	0.3	140 g	19		27	titanium	20 mg	22		47	yttrium	0.6 mg	39
8	sulfur	0.20%	0.3	140 g	16		28	boron	18 mg	5		48	bismuth	0.5 mg	83
9	sodium	0.14%	0.2	100 g	11		29	nickel	15 mg	28		49	thallium	0.5 mg	81
10	chlorine	0.14%	0.2	95 g	17		30	selenium	15 mg	34		50	indium	0.4 mg	49
11	magnesium	0.03%	0.0	19 g	12		31	chromium	14 mg	24		51	gold	0.2 mg	79
12	iron	0.01%	0.0	4.2 g	26		32	manganese	12 mg	25		52	scandium	0.2 mg	21
13	fluorine	0.0037%	0.0	2.6 g	9		33	arsenic	7 mg	33		53	tantalum	0.2 mg	73
14	zinc	0.0033%	0.0	2.3 g	30		34	lithium	7 mg	3		54	vanadium	0.11 mg	23
15	silicon	0.0014%	0.0	1.0 g	14		35	cesium	6 mg	55		55	thorium	0.1 mg	90
16	rubidium	0.0010%	0.0	0.68 g	44		36	mercury	6 mg	80		56	uranium	0.1 mg	92
17	strontium	0.0005%	0.0	0.32 g	38		37	germanium	5 mg	32		57	samarium	50 µg	62
18	bromine	0.0004%	0.0	0.26 g	35		38	molybdenum	5 mg	42		58	beryllium	36 µg	4
19	lead	0.0002%	0.0	0.12 g	82		39	cobalt	3 mg	27		59	tungsten	20 µg	74
20	copper	0.0001%	0.0	72 mg	29		40	antimony	2 mg	51
Chemical composition of a 154-pound healthy adult by the weight of each element. The top 12 elements constitute more than 99.9% of the total weight;  In fact the first 7 elements account for 99.4%. Oxygen and hydrogen appear primarily in the form of water (H2O), nitrogen is primarily in muscle, while calcium and phosphorous are the main components of bone. Potassium and sodium ionize from salts and push nutrients into cells, while iron enables the transport of oxygen.