Lewis Diagrams PDF
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These are practice questions on drawing Lewis diagrams for various compounds. The questions guide students through steps like determining valence electrons, drawing a skeleton structure, and adding lone pairs to fulfill octets. The document includes worked examples and some questions for independent practice.
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2.5 TOPIC: 2.5 LEWIS DIAGRAMS ENDURING UNDERSTANDING: SAP-4 Molecular compounds are arranged based on Lewis diagrams and Valence Shell Electron Pair Repulsion (VSEPR) theory. LEARNING OBJECTIVE: SAP-4.A Represent a molecule with a Lewis diagram. ESSENTIAL KNOWLEDGE: SAP-4.A....
2.5 TOPIC: 2.5 LEWIS DIAGRAMS ENDURING UNDERSTANDING: SAP-4 Molecular compounds are arranged based on Lewis diagrams and Valence Shell Electron Pair Repulsion (VSEPR) theory. LEARNING OBJECTIVE: SAP-4.A Represent a molecule with a Lewis diagram. ESSENTIAL KNOWLEDGE: SAP-4.A.1 Lewis diagrams can be constructed according to an established set of principles. EQUATION(S): N/A NOTES: A Lewis structure shows a representation of how the atoms connect to form a molecule. Lewis structures must account for all electrons in a molecule. A line or a pair of dots between two atoms represents a shared pair of electrons forming a single covalent bond. Two lines or 4 dots between two atoms represent two shared pairs of electrons forming a double covalent bond. Three lines or 6 dots between two atoms represent three shared pairs of electrons forming a triple covalent bond. A pair of electrons on a single atom is called a “lone pair” of electrons. HOW TO DRAW A LEWIS STRUCTURE: 1) Determine the total number of valence electrons in an atom. (Use the Group A column number) 2) Draw a skeleton structure. This places a single bond between atoms as a starting point. The atom that needs to make the most bonds to fill its octet (8 shared electrons) is usually placed in the center; this is usually the least electronegative element. Hydrogens and halogen atoms are almost always terminal (on the ends). Elements in the third period are capable of expanding their octet to share to have more than eight electrons when they are a central atom. 3) Place the remaining electrons as lone pairs so that you can fulfill as many octets as possible. Starting with the most electronegative atoms and/or the outside elements, and work inwards. 4) If you run out of electrons before fulfilling the octets add double bonds or triple bonds as needed. Step 1 Step 2 Step 3 Step 4 CH3OH.. N/A C=4 O—H :O—H H = 4(1) | | O = 1 (6) H—C—H H—C—H = 14 electrons | | H H (10 electrons shown) (14 electrons shown) CH2O.. C=4 O :O: :O: H = 2(1) | | || O = 1 (6) H—C—H H—C—H H—C—H = 12 electrons (6 electrons shown) (12 electrons shown but (12 electrons shown, octet octet not complete for C) complete for all) 1 2.5 I DO: Draw a Lewis diagram for C2H3Cl Step 1 Step 2 Step 3 Step 4 CH3Cl HH HH HH C = 2(4) || ||.. ||.. H = 3(1) H—C—C—Cl H—C—C—Cl : H—C=C—Cl : Cl = 7.... (16 electrons shown, octet = 18 electrons not complete for carbons) (18 electrons shown) (10 electrons shown) WE DO: Draw a Lewis diagram for the following: A) C2H2 B) OH- C) CF2S D) BCl3 E) SF6 YOU DO: Draw a Lewis diagram for the following: 1) NCl3 2) NOCl 3) CH2Cl2 4) N2 2 2.5 5) C2H5F 6) XeF4 7) PCl5 8) Butyric Acid, C4H8O2, is partially shown below. Complete the diagram, include all lone pairs. HHH ||| H—C—C—C—C ||| HHH 3
