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Cl Chlorine
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

17
Cl
Chlorine
Element 17 of Periodic table is Chlorine with atomic number 17, atomic weight 35.453. Chlorine, symbol Cl, has a Base Centered Orthorhombic structure and Yellow color. Chlorine is a Halogens element. It is part of group 17 (fluorine family). Know everything about Chlorine Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
17 Cl - Chlorine | SchoolMyKids

Chlorine is a chemical element with symbol Cl and atomic number 17. It also has a relative atomic mass of 35.5. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine.

It belongs to group 17 of the periodic table having trivial name halogens.

Chlorine Facts

Read key information and facts about element Chlorine

NameChlorine
Atomic Number17
Atomic SymbolCl
Atomic Weight35.453
PhaseGas (Diatomic Gas )
ColorYellow
Appearancepale yellow-green gas
ClassificationHalogens
Group in Periodic Table17
Group Namefluorine family
Period in Periodic Tableperiod 3
Block in Periodic Tablep -block
Electronic Configuration[Ne] 3s2 3p5
Electronic Shell Structure (Electrons per shell)2, 8, 7
Melting Point171.6 K
Boiling Point239.11 K
CAS NumberCAS7782-50-5
Neighborhood Elements
123456789101112131415161718
1
1
H
Hydrogen
1.008

Atomic #

Electronic Shell #

Symbol
Name
Atomic Weight
HGas
HgLiquid
CSolid
Metals
Metalloids
NonMetals
Alkali metals
Alkali earth metals
Lanthanoids
Transition metals
Post-transition metals
Other nonmetals
Halogens
Nobel gas
Actinoids
2
He
Helium
4.003
2
3
Li
Lithium
6.941
4
Be
Beryllium
9.012
5
B
Boron
10.811
6
C
Carbon
12.011
7
N
Nitrogen
14.007
8
O
Oxygen
15.999
9
F
Fluorine
18.998
10
Ne
Neon
20.180
3
11
Na
Sodium
22.990
12
Mg
Magnesium
24.305
13
Al
Aluminium
26.982
14
Si
Silicon
28.085
15
P
Phosphorus
30.974
16
S
Sulfur
32.065
17
Cl
Chlorine
35.453
18
Ar
Argon
39.948
4
19
K
Potassium
39.098
20
Ca
Calcium
40.078
21
Sc
Scandium
44.956
22
Ti
Titanium
47.867
23
V
Vanadium
50.941
24
Cr
Chromium
51.996
25
Mn
Manganese
54.938
26
Fe
Iron
55.845
27
Co
Cobalt
58.933
28
Ni
Nickel
58.693
29
Cu
Copper
63.546
30
Zn
Zinc
65.409
31
Ga
Gallium
69.723
32
Ge
Germanium
72.640
33
As
Arsenic
74.922
34
Se
Selenium
78.960
35
Br
Bromine
79.904
36
Kr
Krypton
83.798
5
37
Rb
Rubidium
85.468
38
Sr
Strontium
87.620
39
Y
Yttrium
88.906
40
Zr
Zirconium
91.224
41
Nb
Niobium
92.906
42
Mo
Molybdenum
95.940
43
Tc
Technetium
98
44
Ru
Ruthenium
101.070
45
Rh
Rhodium
102.906
46
Pd
Palladium
106.420
47
Ag
Silver
107.868
48
Cd
Cadmium
112.411
49
In
Indium
114.818
50
Sn
Tin
118.710
51
Sb
Antimony
121.760
52
Te
Tellurium
127.600
53
I
Iodine
126.904
54
Xe
Xenon
131.293
6
55
Cs
Cesium
132.905
56
Ba
Barium
137.327
57 - 71
La - Lu
Lanthanides
72
Hf
Hafnium
178.490
73
Ta
Tantalum
180.948
74
W
Tungsten
183.840
75
Re
Rhenium
186.207
76
Os
Osmium
190.230
77
Ir
Iridium
192.217
78
Pt
Platinum
195.078
79
Au
Gold
196.967
80
Hg
Mercury
200.590
81
Tl
Thallium
204.383
82
Pb
Lead
207.200
83
Bi
Bismuth
208.980
84
Po
Polonium
209
85
At
Astatine
210
86
Rn
Radon
222
7
87
Fr
Francium
223
88
Ra
Radium
226
89 - 103
Ac - Lr
Actinides
104
Rf
Rutherfordium
261
105
Db
Dubnium
262
106
Sg
Seaborgium
266
107
Bh
Bohrium
264
108
Hs
Hassium
277
109
Mt
Meitnerium
268
110
Ds
Darmstadtium
281
111
Rg
Roentgenium
272
112
Cn
Copernicium
285
113
Nh
Nihonium
284
114
Fl
Flerovium
289
115
Mc
Moscovium
288
116
Lv
Livermorium
292
117
Ts
Tennessine
294
118
Og
Oganesson
294
Lanthanides
57
La
Lanthanum
138.905
58
Ce
Cerium
140.116
59
Pr
Praseodymium
140.908
60
Nd
Neodymium
144.240
61
Pm
Promethium
145
62
Sm
Samarium
150.360
63
Eu
Europium
151.964
64
Gd
Gadolinium
157.250
65
Tb
Terbium
158.925
66
Dy
Dysprosium
162.500
67
Ho
Holmium
164.930
68
Er
Erbium
167.259
69
Tm
Thulium
168.934
70
Yb
Ytterbium
173.040
71
Lu
Lutetium
174.967
Actinides
89
Ac
Actinium
227
90
Th
Thorium
232.038
91
Pa
Protactinium
231.036
92
U
Uranium
238.029
93
Np
Neptunium
237
94
Pu
Plutonium
244
95
Am
Americium
243
96
Cm
Curium
247
97
Bk
Berkelium
247
98
Cf
Californium
251
99
Es
Einsteinium
252
100
Fm
Fermium
257
101
Md
Mendelevium
258
102
No
Nobelium
259
103
Lr
Lawrencium
262

How to Locate Chlorine on Periodic Table

Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 17 to find Chlorine on periodic table.

Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Chlorine on periodic table look for cross section of group 17 and period 3 in the modern periodic table.

Chlorine History

The element Chlorine was discovered by W. Scheele in year 1774 in Sweden. Chlorine was first isolated by W. Scheele in 1774. Chlorine derived its name from the Greek word chloros, meaning 'greenish yellow'.

Obtained it from hydrochloric acid, but thought it was an oxide. Only in 1808 did Humphry Davy recognize it as an element.

Chlorine Presence: Abundance in Nature and Around Us

The table below shows the abundance of Chlorine in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.

 ppb by weight (1ppb =10^-7 %)ppb by atoms (1ppb =10^-7 %)
Abundance in Universe100040
Abundance in Sun8000300
Abundance in Meteorites380000160000
Abundance in Earth's Crust170000100000
Abundance in Oceans198700003470000
Abundance in Humans1200000210000

Crystal Structure of Chlorine

The solid state structure of Chlorine is Base Centered Orthorhombic.

The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.

Unit Cell Parameters

The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)

abc
622.35 pm445.61 pm817.85 pm

and the angles between them Lattice Angles (alpha, beta and gamma).

alphabetagamma
π/2 π/2 π/2

The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.

The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.

Space Group NameCmca 17 Cl Chlorine - Crystal Structure | SchoolMyKids
Oxidation StatesSpace Group Number64
Crystal StructureBase Centered Orthorhombic

Chlorine Atomic and Orbital Properties

Chlorine atoms have 17 electrons and the electronic shell structure is [2, 8, 7] with Atomic Term Symbol (Quantum Numbers) 2P3/2.

Atomic Number17
Number of Electrons (with no charge)17
Number of Protons17
Mass Number35
Number of Neutrons18
Shell structure (Electrons per energy level)2, 8, 7
Electron Configuration[Ne] 3s2 3p5
Valence Electrons3s2 3p5
Valence (Valency)5
Main Oxidation States-1, 1, 3, 5, 7
Oxidation States-1, 1, 2, 3, 4, 5, 6, 7
Atomic Term Symbol (Quantum Numbers)2P3/2

Bohr Atomic Model of Chlorine - Electrons per energy level

17 Cl Chlorine - Electron Shell Structure | SchoolMyKids
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Ground State Electronic Configuration of Chlorine - neutral Chlorine atom

Abbreviated electronic configuration of Chlorine

The ground state abbreviated electronic configuration of Neutral Chlorine atom is [Ne] 3s2 3p5. The portion of Chlorine configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Ne]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 3s2 3p5, electrons in the outermost shell that determine the chemical properties of the element.

Unabbreviated electronic configuration of neutral Chlorine

Complete ground state electronic configuration for the Chlorine atom, Unabbreviated electronic configuration

1s2 2s2 2p6 3s2 3p5

Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.

  • As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
  • The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
  • Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
  • Electron configuration of Chlorine
    Atomic Structure of Chlorine

    Chlorine atomic radius is 79 pm, while it's covalent radius is 99 pm.

    Atomic Radius Calculated

    79 pm (0.79 Å)

    Atomic Radius Empirical

    100 pm (1 Å)

    Atomic Volume22.4129 cm3/mol
    Covalent Radius99 pm (0.99 Å)
    Van der Waals Radius175 pm
    Neutron Cross Section35.3
    Neutron Mass Absorption 0.033

    Atomic Spectrum of Chlorine

    Atomic Spectrum of Chlorine | SchoolMyKids

    Chlorine Chemical Properties: Chlorine Ionization Energies and electron affinity

    The electron affinity of Chlorine is 349 kJ/mol.

    Valence5
    Electronegativity3.16
    ElectronAffinity349 kJ/mol

    Ionization Energy of Chlorine

    Refer to table below for Ionization energies of Chlorine

    Ionization energy numberEnthalpy - kJ/mol
    1st1251.2
    2nd2298
    3rd3822
    4th5158.6
    5th6542
    6th9362
    7th11018
    8th33604
    9th38600
    10th43961
    11th51068
    12th57119
    13th63363
    14th72341
    15th78095
    16th352994
    17th380760

    Chlorine Physical Properties

    Refer to below table for Chlorine Physical Properties

    Density0.003214 g/cm3
    Molar Volume22.4129 cm3/mol

    Elastic Properties

    Young Modulus-
    Shear Modulus-
    Bulk Modulus 1.1 GPa
    Poisson Ratio-

    Hardness of Chlorine - Tests to Measure of Hardness of Element

    Mohs Hardness-
    Vickers Hardness-
    Brinell Hardness-

    Chlorine Electrical Properties

    Chlorine is Conductor of electricity. Refer to table below for the Electrical properties ofChlorine

    Electrical Conductivity0.01 S/m
    Resistivity100 m Ω
    Superconducting Point-

    Chlorine Heat and Conduction Properties

    Thermal Conductivity0.0089 W/(m K)
    Thermal Expansion-

    Chlorine Magnetic Properties

    Magnetic TypeDiamagnetic
    Curie Point-
    Mass Magnetic Susceptibility-7.2e-9 m3/kg
    Molar Magnetic Susceptibility-5.11e-10 m3/mol
    Volume Magnetic Susceptibility-2.31e-8

    Optical Properties of Chlorine

    Refractive Index1.000773

    Acoustic Properties of Chlorine

    Speed of Sound206 m/s

    Chlorine Thermal Properties - Enthalpies and thermodynamics

    Refer to table below for Thermal properties of Chlorine

    Melting Point171.6 K (-101.55°C, -150.78999999999996 °F)
    Boiling Point239.11 K (-34.04°C, -29.271999999999935 °F)
    Critical Temperature416.9 K
    Superconducting Point-

    Enthalpies of Chlorine

    Heat of Fusion3.2 kJ/mol
    Heat of Vaporization10.2 kJ/mol
    Heat of Combustion-

    Chlorine Isotopes - Nuclear Properties of Chlorine

    Chlorine has 24 isotopes, with between 28 and 51 nucleons. Chlorine has 2 stable naturally occuring isotopes.

    Isotopes of Chlorine - Naturally occurring stable Isotopes: 35Cl, 37Cl.

    IsotopeZNIsotope Mass% AbundanceT halfDecay Mode
    28Cl171128Synthetic
    29Cl171229Synthetic
    30Cl171330Synthetic
    31Cl171431Synthetic
    32Cl171532Synthetic
    33Cl171633Synthetic
    34Cl171734Synthetic
    35Cl17183575.78%Stable
    36Cl171936Synthetic
    37Cl17203724.22%StableN/A
    38Cl172138Synthetic
    39Cl172239Synthetic
    40Cl172340Synthetic
    41Cl172441Synthetic
    42Cl172542Synthetic
    43Cl172643Synthetic
    44Cl172744Synthetic
    45Cl172845Synthetic
    46Cl172946Synthetic
    47Cl173047Synthetic
    48Cl173148Synthetic
    49Cl173249Synthetic
    50Cl173350Synthetic
    51Cl173451Synthetic

    Database Search

    List of unique identifiers to search the element in various chemical registry databases

    DatabaseIdentifier number
    CAS Number - Chemical Abstracts Service (CAS)CAS7782-50-5
    RTECS NumberRTECSFO2100000
    CID Number CID24526
    Gmelin Number-
    NSC Number-