Atomic No. Order:

Alphabetic Order:

Periodic Table

2, 8, 18, 32,

18, 8, 2

Be
4

Mg
12

Ca
20

Sr
38

Ba
56

Ra
88

Ubn 120

Usn
170

Bbn
220

Radium

Symbol

Atomic Number

Relative Atomic Mass
¹²C = 12.0000

[ 226 ]

Significant Atomic Mass

225
Neutrons 137

Atomic Radius pm

223

First Ionisation Energy
kJ mol ^-1

509.3

Ionization energy (eV)

5,2784

Electronegativity

0.89

Density kg m ^-3

c. 5000 [293 K]

Molar Volume cm ³

45.2

Thermal Conductivity
W m ^-1 K ^-1

18.6 [300 K] (est.)

Melting Point K

973

Boiling Point K

1413

Isotopes

223

223.0185

11.43(1) day

224

224.0202

3.66(2) day

226

226.0254

1599(4) year

228

228.0311

5.75(3) year

Number of Isotopes

Inner + outer Shells

Inner + outer Orbitals

Filling Orbital

7s ²

Ground State Electron
Configuration

[Rn]

5d ¹⁰ 6p ⁶

7s ²

Ground State Electron
Configuration with
free Orbital (n= 30 )

0, 0, 0, 0, 14, 10, 6

Ground State Electron
Configuration with
compr. Orbitals (n= 162 )

0, 0, 0, 0, 18, 54, 90

Singularity S(n)

280

162

	s	p	d	f	g	h	i	j
1	2
2	2	6
3	2	6	10
4	2	6	10	14
5	2	6	10	14	18
6	2	6	10	14	18	22
7	2	6	10	14	18	22	26
8

Term Symbol

¹S₀

Discovery

Discovered by P. Curie and M. Curie (Paris, France) in 1898. Isolated by M. Curie in 1911

Name Derived From

Latin radius meaning 'ray'

Decompression of outer-orbitals/shells at the example of Radium

APSIDIUM	Created:	2002-08-13	088.pdf
	Page update:	2005-09-10	088.pdf

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