3e. The covalent bonding in the chlorine molecule

Doc Brown's Chemistry: Chemical Bonding and structure GCSE level, IGCSE, O, IB, AS, A level US grade 9-12 level Revision Notes

Covalent bonding diagram for CHLORINE covalent molecule, molecular formula Cl2

* metals \ non-metals (zig-zag line)

Pd metals Part of the modern Periodic Table

Pd = period, Gp = group

metals => non–metals
Gp1 Gp2 Gp3 Gp4 Gp5 Gp6 Gp7 Gp0
1 1H  Note that hydrogen does not readily fit into any group but is a non-metal 2He
2 3Li 4Be atomic number Chemical Symbol eg 4Be 5B 6C 7N 8O 9F 10Ne
3 11Na 12Mg 13Al 14Si 15P 16S 17Cl 18Ar
4 19K 20Ca 21Sc 22Ti 23V 24Cr 25Mn 26Fe 27Co 28Ni 29Cu 30Zn 31Ga 32Ge 33As 34Se 35Br 36Kr
5 37Rb 38Sr 39Y 40Zr 41Nb 42Mo 43Tc 44Ru 45Rh 46Pd 47Ag 48Cd 49In 50Sn 51Sb 52Te 53I 54Xe
6 55Cs 56Ba Transition Metals 81Tl 82Pb 83Bi 84Po 85At 86Rn
The covalent molecule chlorine from combining with itself


Two chlorine atoms (2.8.7) form the molecule of the element chlorine Cl2

Chlorine, a Cl atom, is one electron short of a full outer shell of 8 like argon (2.8.8), so two chlorine atoms share an electron to have full outer shells.

(c) doc b and (c) doc b combine to form (c) doc b where both atoms have a pseudo argon structure of 8 outer electrons around each atom. The electronic dot & cross Lewis diagrams for covalent bonding in chlorine - outer shell electrons only.

(Lewis diagram of chlorine on the left) simplified 'dot and cross' electronic diagram for the covalently bonded chlorine molecule

dot and cross diagram of the chlorine moleculeThe chlorine molecule is held together by the strong chlorine–chlorine single covalent bond from sharing outer electrons,  Cl–Cl (displayed formula)..

(c) doc bElectronically, both chlorines (2.8.7) become like argon (2.8.8), so the chlorine atoms effectively have a full outer shell in forming the covalent bonds when the atoms share their outer electrons.

All the other halogens would be similar e.g. F2, Br2 and I2 etc.

Here the valency of halogens like chlorine is 1.


Note that the two inner shells of chlorine's electrons are not shown some diagrams above, but they are in the diagram on the left, and, remember, 'dots' and 'crosses' are all the same electrons in their specific energy levels and only the outer shells of electrons are involved in the covalent bonding here.

 This the full 'dot and cross' electronic diagram for the covalent bonding in the chlorine molecule.


ball and stick diagram for chlorine

  space-filling model of chlorine



Melting point of chlorine -101 oC

Boiling point of chlorine -34 oC

Chlorine is a poisonous-toxic green gas at room temperature






What next?

Recommend next: The covalent bonding in hydrogen chloride

Explaining the properties of small covalently bonded molecules


Sub-index for Part 3. Covalent Bonding: small molecules & properties


Index for ALL chemical bonding and structure notes


Perhaps of interest?

The Group 7 Halogens


Use My Google search box

Website map buttons below


KS3 BIOLOGY QUIZZES ~US grades 6-8 KS3 CHEMISTRY QUIZZES ~US grades 6-8 KS3 PHYSICS QUIZZES ~US grades 6-8 HOMEPAGE of Doc Brown's Science Website EMAIL Doc Brown's Science Website
GCSE 9-1 BIOLOGY NOTES GCSE 9-1 CHEMISTRY NOTES and QUIZZES GCSE 9-1 PHYSICS NOTES GCSE 9-1 SCIENCES syllabus-specification help links for biology chemistry physics courses IGCSE & O Level SCIENCES syllabus-specification help links for biology chemistry physics courses
Advanced A/AS Level ORGANIC Chemistry Revision Notes US K12 ~grades 11-12 Advanced A/AS Level INORGANIC Chemistry Revision Notes US K12 ~grades 11-12 Advanced A/AS Level PHYSICAL-THEORETICAL Chemistry Revision Notes US K12 ~grades 11-12 Advanced A/AS Level CHEMISTRY syllabus-specificatio HELP LINKS of my site Doc Brown's Travel Pictures
Website content © Dr Phil Brown 2000+. All copyrights reserved on revision notes, images, quizzes, worksheets etc. Copying of website material is NOT permitted. Exam revision summaries & references to science course specifications are unofficial.

 Doc Brown's Chemistry