Thallium Element (Periodic Table)

Thallium (Tl) is a chemical element of the periodic table, located in the group 13 and the period 6, and has the atomic number 81. It is a soft, malleable, lustrous, silvery-grey post transition metal, whose name comes from the Greek word “thallos”, which means green twig. It is highly toxic and is not available freely in nature. It is a member of the boron group.

group

period

1
H

2
He

3
Li

4
Be

5
B

6
C

7
N

8
O

9
F

10
Ne

11
Na

12
Mg

13
Al

14
Si

15
P

16
S

17
Cl

18
Ar

19
K

20
Ca

21
Sc

22
Ti

23
V

24
Cr

25
Mn

26
Fe

27
Co

28
Ni

29
Cu

30
Zn

31
Ga

32
Ge

33
As

34
Se

35
Br

36
Kr

37
Rb

38
Sr

39
Y

40
Zr

41
Nb

42
Mo

43
Tc

44
Ru

45
Rh

46
Pd

47
Ag

48
Cd

49
In

50
Sn

51
Sb

52
Te

53
I

54
Xe

55
Cs

56
Ba

72
Hf

73
Ta

74
W

75
Re

76
Os

77
Ir

78
Pt

79
Au

80
Hg

81
Tl

82
Pb

83
Bi

84
Po

85
At

86
Rn

87
Fr

88
Ra

104
Rf

105
Db

106
Sg

107
Bh

108
Hs

109
Mt

110
Ds

111
Rg

112
Cn

113
Nh

114
Fl

115
Mc

116
Lv

117
Ts

118
Og

57
La

58
Ce

59
Pr

60
Nd

61
Pm

62
Sm

63
Eu

64
Gd

65
Tb

66
Dy

67
Ho

68
Er

69
Tm

70
Yb

71
Lu

89
Ac

90
Th

91
Pa

92
U

93
Np

94
Pu

95
Am

96
Cm

97
Bk

98
Cf

99
Es

100
Fm

101
Md

102
No

103
Lr

– p block

FAQs on Thallium Element

Thallium
‣ What does thallium look like? Appearance: silvery white
‣ Who discovered thallium? When was the element thallium discovered? Discovery: William Crookes (1861) First isolation: Claude-Auguste Lamy (1862)
‣ Where is thallium located on the periodic table? Location: Thallium is found in the sixth row of the periodic table below the indium element.
‣ What is the atomic number for thallium? Atomic number (Z): 81
‣ What is thallium symbol? Symbol: Tl
‣ Thallium atomic weight: [204.382, 204.385] conventional: 204.38
‣ What block is thallium in the periodic table? Block: p-block
‣ What group does thallium belong to? Group: 13 (boron group)
‣ What period is thallium on the periodic table? Period: 6
‣ Thallium atomic radius: empirical: 170 pm
‣ Thallium covalent radius: 145±7 pm
‣ Thallium Van der Waals radius: 196 pm
‣ What is thallium melting point? Melting point: 577 K (304 °C, 579 °F)
‣ What is the boiling point of thallium? Boiling point: 1746 K (1473 °C, 2683 °F)
‣ How many electron shells does thallium have? Electrons per shell: 2, 8, 18, 32, 18, 3
‣ What is the electron configuration of thallium? Electron configuration: [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹
‣ Thallium ionization energies: 1st: 589.4 kJ/mol 2nd: 1971 kJ/mol 3rd: 2878 kJ/mol
‣ What is the phase of thallium? Phase (at r.t): solid
‣ Thallium density (near r.t): 11.85 g/cm³ when liquid (at m.p): 11.22 g/cm³
‣ Thallium magnetic ordering: diamagnetic
‣ Thallium natural occurrence: primordial
‣ What is the oxidation state of thallium? Oxidation state: +1, +3
‣ What’s the electronegativity of thallium? Electronegativity: Pauling scale: 1.62
‣ Thallium poisson’s ratio: 0.45
‣ Thallium heat of fusion: 4.14 kJ/mol
‣ Thallium heat of vaporization: 165 kJ/mol
‣ Thallium molar heat capacity: 26.32 J/(mol K)
‣ Thallium molar magnetic susceptibility: -50.9 × 10^-6 cm³/mol (298 K)
‣ Speed of sound in thallium: 818 m/s (at 20 °C)
‣ What is the crystal structure of thallium? Crystal structure: hexagonal close-packed (hcp)
‣ Thermal expansion of thallium: 29.9 µm/(m.K) (at 25 °C)
‣ Thermal conductivity of thallium: 46.1 W/(m.K)
‣ Thallium electrical resistivity: 0.18 nΩ.m (at 20 °C)
‣ Thallium hardness Mohs hardness: 1.2 Brinell hardness: 26.5-44.7 MPa
‣ Young’s modulus of thallium: 8 GPa
‣ Shear modulus of thallium: 2.8 GPa
‣ Bulk modulus of thallium: 43 GPa
‣ Thallium CAS number: 7440-28-0

‣ Thallium vapor pressure

Vapor pressure
P (Pa)	1	10	100	1 k	10 k	100 k
at T (K)	882	977	1097	1252	1461	1758

‣ How many isotopes does thallium have?

Main isotopes of thallium
Isotope	Abundance	Half-life (t_1/2)	Decay mode	Product
²⁰³Tl	29.5 %		stable
²⁰⁴Tl	syn	3.78 y	β^– ε	²⁰⁴Pb ²⁰⁴Hg
²⁰⁵Tl	70.5 %		stable

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Related:

Periodic Table of Elements

Also Read:

FAQs on Thallium Element

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