Praseodymium 59

Atomic No. Order:

Alphabetic Order:

Periodic Table

2, 8, 18,

21, 8, 2

Pr
59

Pa
91

Uqu
141

Ueu
191

Praseodymium

Symbol

Atomic Number

Relative Atomic Mass
¹²C = 12.0000

140.90765 (2) [Since 1995]

Atomic Radius pm

183

First Ionisation Energy
kJ mol ^-1

523.1

Electronegativity

1.13

Density kg m ^-3

6773 [293 K]

Molar Volume cm ³

20.80

Thermal Conductivity
W m ^-1 K ^-1

12.5 [300 K]

Melting Point K

1204

Boiling Point K

3785

Number of Isotopes

Isotope Atomic mass/u Mole fraction

141Pr 140.907 648(3) 1.0000

Inner/outer Shells

Inner/outer Orbitals

Filling Orbital

4f ³

Ground State Electron Configuration

[Xe]

4f ³

5p ⁶

6s ²

Ground State Electron Configuration with free Orbitals (n=27)

0, 0, 0, 11, 10, 6

Ground State Electron Configura tion with compressed Orbitals (n=96)

0, 0, 0, 0, 32, 64

Singularity

182

	s	p	d	f		g	h	i	j
1	2
2	2	6
3	2	6	10
4	2	6	10	3	11
5	2	6	10	14		18
6	2	6	10	14		18	22
7
8

Term Symbol

⁴I _9/2

Discovery

Baron Auer von Welsbach (Vienna, Austria) in 1885

Name Derived From

The name derives from the Greek prasios for "green" and didymos for "twin" because of the pale green salts it forms. It was discovered by the Austrian chemist Carl Auer von Welsbach in 1885, who separated it and the element neodymium from a didymium sample. Didymium had previously been thought to be a separate element.

APSIDIUM ©	Created:		2002-07-26		059.pdf
	Page update:		2004-12-06		059.pdf