Lanthanum

LANTHANOID · GROUP None · PERIOD 6

Lanthanum

138.91

Atomic Data

[Xe] 5d¹ 6s²

Shell	n	Subshell	Electrons	Cumulative
K	1	1s	2	2
L	2	2s	2	4
L	2	2p	6	10
M	3	3s	2	12
M	3	3p	6	18
M	3	3d	10	28
N	4	4s	2	30
N	4	4p	6	36
N	4	4d	10	46
O	5	5s	2	48
O	5	5p	6	54
O	5	5d	1	55
P	6	6s	2	57
Total			57	57

Lanthanum has two naturally occurring stable isotopes. The most abundant is ¹³⁹La, comprising 99.91% of all naturally occurring Lanthanum.

Isotope	Symbol	Protons	Neutrons	Abundance	Stability
Lanthanum-138	¹³⁸La	57	81	0.09	Stable
Lanthanum-139	¹³⁹La	57	82	99.91	Stable

Lanthanum is present in Earth's crust at approximately 39 ppm by mass and at approximately 2 ppm by mass throughout the universe.

Lanthanum

39 ppm

Silicon (ref.)

277,000 ppm

Oxygen (ref.)

461,000 ppm

Lanthanum

2 ppm

Helium (ref.)

230,000 ppm

Hydrogen (ref.)

739,000 ppm

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