Calcium 20

Atomic No. Order:

Alphabetic Order:

Periodic Table

2, 8,

8, 2

Be
4

Mg
12

Ca
20

Sr
38

Ba
56

Ra
88

Ubn
120

Usn
170

Bbn
220

Calcium

Symbol

Atomic Number

Relative Atomic Mass
¹²C = 12.0000

40.078 (±4) [Since 1983]

Atomic Radius pm

197 (±-form)

First Ionisation Energy
kJ mol ^-1

589.7

Ionisation Energy (eV)

6.1132

Electronegativity

1.00

Density
kg m ^-3

1550 [293 K]
1365 [m.p.]

Molar Volume cm ³

25.86

Thermal Conductivity
W m ^-1 K ^-1

200 [300 K]

Melting Point K

1112

Boiling Point K

1757

Number of Isotopes

Isotope Atomic mass/u Mole fraction

40Ca 39.962 5912(3) 0.969 41(156)
42Ca 41.958 6183(4) 0.006 47(23)
43Ca 42.958 7668(5) 0.001 35(10)
44Ca 43.955 4811(9) 0.020 86(110)
46Ca 45.953 6927(25) 0.000 04(3)
48Ca 47.952 533(4) 0.001 87(21)

Inner + outer Shells

Inner + outer Orbitals

Filling Orbital

4s ²

Ground State Electron
Configuration

Ar]

4s ²

Ground State Electron
Configuration with
free Orbitals (n= 16)

0, 0, 10, 6

Ground State Electron
Configuration with
compressed Orbitals (n= 24)

0, 0, 0, 24

Singularity

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

Term Symbol

¹S ₀

Discovery

It was first isolated by chemist Sir Humphry Davy (London, England) in 1808 with help from the Swedish chemist J öns Jacob Berzelius and the Swedish court physician M. M. af Pontin.

Name Derived From

The name derives from the Latin calx for "lime (CaO)" or "limestone (CaCO ₃)" in which it was found.

APSIDIUM ©	Created:	2002- 06-04	020.pdf
	Page update:	2004-06-20	020.pdf