MolView is an intuitive, Open-Source web-application to make science and education more awesome! Remember, formal charges can sometimes help you decide which is the best Lewis Dot Structure when there is more than one possible structure. Draw the best Lewis Dot Structure for each of the following species. A) BeF 2 b) BCl 3 c) CCl 4 d) PBr 5 e) SI 6. Give the name of the electronic arrangement and the name for the molecular geometry for. Get the free 'Lewis structure' widget for your website, blog, Wordpress, Blogger, or iGoogle. Find more Chemistry widgets in Wolfram Alpha. The ChemDoodle Web Components (CWC) library is a pure JavaScript chemical graphics and cheminformatics library derived from the ChemDoodle ® application and produced by iChemLabs. ChemDoodle Web Components allow the wielder to present publication quality 2D and 3D graphics and animations for chemical structures, reactions and spectra. Lewis Structures. A Lewis dot structure is a two-dimensional sketch of a molecule that uses dots to represent valence electrons. The Lewis structure helps us identify the type of bonding that may be present in a molecule based on the number of valence electrons available.

In 1916, ten years before the Schrodinger wave equation, G. N. Lewis suggested that a chemical bond involved sharing of electrons. He described what he called the cubical atom, because a cube has 8 corners, to represent the outer valence shell electrons which can be shared to create a bond. This was his octet rule.

Lewis Electron Dot Structure Calculator

1. Count the number of valence e^- each atom brings into the molecule.For ions, the charge must be taken into account.

   How many valence electrons in BeCl₂?

   How many valence electrons in NO₂^- and NO₂⁺?

2. Put electron pairs about each atom such that there are 8 electrons around each atom (octet rule), with the exception of H, which is only surrounded by 2 electrons. Sometimes it's necessary to form double and triple bonds. Only C, N, O, P and S (rarely Cl) will form multiple bonds.

   Draw the Lewis dot structure for CF₄.

   The number of valence electrons is 4 + 4 ( 7 ) = 32 electrons.

   So, we obtain:

   Draw the Lewis dot structure for CO.

   The number of valence electrons is 4 + 6 = 10 electrons or 5 pairs. Since both C and O allow multiple bonds we can still follow the octet and write:

3. If there is not enough electrons to follow the octet rule, then the least electronegative atom is left short of electrons.

   Draw the Lewis dot structure for BeF₂.

   In BeF₂ number of valence e^- = 2+ 2(7) = 16 e^- or 8 pairs. Since neither Be or F form multiple bonds readily and Be is least electronegative we obtain:

4. If there are too many electrons to follow the octet rule, then the extra electrons are placed on the central atom.

   Draw the Lewis dot structure for SF₄.

   In SF₄ the number of valence electrons is 6 + 4 ( 7 ) = 34 electrons or 17 pairs. Placing the extra electrons on S we obtain:

How can the octet rule be violated in this last example? The octet rule arises because the s and p orbitals can take on up to 8 electrons. However, once we reach the third row of elements in the periodic table we also have d-orbitals, and these orbitals help take the extra electrons. Note that you still need to know how the atoms are connected in a polyatomic molecule before using the Lewis-Dot structure rules.

Homework from Chemisty, The Central Science, 10th Ed.

Covalent Lewis Dot Structure Calculator

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