Na 11 1s 2 2s 2 2p 6 3s 1 1 Na. Mg 12 1s 2 2s 2 2p 6 3s 2 2 Mg. O 8 1s 2 2s 2 2p 4 6 O. Al 13 1s 2 2s 2 2p 6 3s 2 3p 1 3 Al. C 6 1s 2 2s 2 2p 2 4 C

Transcription

1 Electron onfigurations, Rutherford-Bohr and Electron Dot Diagrams Remember, when drawing electron dot diagrams: Write the symbol for the element and show only the outer (valence) electrons The number of valence electrons is equal to the Group Number (in Roman Numerals) for each element ollow the convention of only doubling up the electrons after all four orbitals have one electron each eg. the electron dot diagram for phosphorus (Group V) would be Element tomic # Electron onfiguration Rutherford-Bohr Diagram # of Valence Electrons Electron Dot Diagram Na 11 1s 2 2s 2 2p 6 3s 1 1 Na Mg 12 1s 2 2s 2 2p 6 3s 2 2 Mg 8 1s 2 2s 2 2p 4 6 l 13 1s 2 2s 2 2p 6 3s 2 3p 1 3 l 6 1s 2 2s 2 2p 2 4 N 7 1s 2 2s 2 2p 3 5 N

2 omework: fter you have completed the above chart, draw the electron dot diagrams for atoms with atomic number 1, 9, 10, 14, 15, 16, 17, 18, 20, 34, 35, 36, 37, 38, 52, 53, 54, 55, 56 and 85 tomic #1: hydrogen tomic #9: fluorine tomic #10: neon tomic #14: silicon Ne i tomic #15: phosphorus tomic #16: sulfur tomic #17: chlorine tomic #18: argon l r tomic #20: calcium tomic #34: selenium tomic #35: bromine tomic #36: krypton a e Kr tomic #37: rubidium tomic #38: strontium tomic #52: tellurium tomic #53: iodine Rb r Te tomic #54: xenon tomic #55: cesium tomic #56: barium tomic #85: astatine e s Ba t

3 nswers to omework: onic Bonding 1. Use EDDs to show the formation of the ionic compounds between: a) Li and Li Li Li [ Li ] 1+ + [ ] 3- + [ Li ] 1+ Li 3 [ Li ] 1+ b) c and N c N [c] 3+ + [ N ] 3 cn c) Ba and Ba [ Ba ] 2+ + [ ] 2- Ba d) l and l l [ ] 2 + [l] 3+ + [ ] 2 + [l] 3+ + [ ] 2 + l 2 3 Questions from pages of text: Q9. ollow steps as shown above a) lithium iodide will have the chemical formula Li b) barium chloride will have the formula Bal 2 c) potassium oxide will have the formula K 2 d) calcium fluoride will have the formula a 2 Q12. ll five halogens will have seven valence electrons in their valence shell. Because all of these elements have the same number of valence electrons, they are part of a chemical family.

4 Q13. ollow steps as shown above a) magnesium chloride: Mgl 2 b) sodium sulfide: Na 2 c) aluminum oxide: l 2 3 d) barium chloride: Bal 2 e) calcium fluoride: a 2 f) sodium iodide: Na g) potassium chloride: Kl ketch of a crystal lattice: l - Na +

5 nswers to omework: ovalent Bonding 1. Read ormation of ovalent Bonds, pages in Nelson hemistry Define octet rule, covalent bond, bonding capacity, molecular formula. ee notes. 3. Explain how a formula unit of an ionic compound is different from the molecular formula of a covalent compound. formula unit is the lowest possible ratio in which the ions combine in an ionic compound. Because all of the negative ions are attracted to all of the positive ions in an ionic compound, the ions arrange themselves in a huge three-dimensional structure called a crystal lattice. There are many positive and negative ions in the crystal lattice, so the formula unit indicates the simplest ratio of positive to negative ions. or example, in calcium chloride (al 2 ), there are two chloride ions for every one calcium ion. molecular formula of a covalent compound is the exact number of each type of atom present in one discrete molecule. or example, glucose has the molecular formula which tells us that there are 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms all chemically bonded together to form one molecule. The molecular formula of a covalent compound can NT be reduced to lower terms, because then it would no longer be the same substance. 4. Draw the Lewis structures (structural formulas) for the following molecules. Be sure to draw in all unshared electron pairs. a) 2 b) l c) 3 d) 4 e) 2 4 f) l 3 g) 2 h) 2 2 l l i) 2 6 j) 2 4 k) 2 2 l) 2 m) N 2 2 n) N 2 o) i 2 p) N 2 N N N N i l q) 3 8 r) 4 10 s) 4 8 (the double bond can be between any two carbon atoms) l N t) 2 5

6 u) N v) 6 14 w) 3 7 N x) y) 3

7 omework: The hapes of Molecules 1. omplete the chart below using E notation (nem) to show the number of bonded electron groups on the central atom (n), number of lone electron pairs (L) on the central atom (m), the total number of electron groups on the central atom (n+m) and the name of the shape of the molecule. Drawing of Molecule E Notation (nem) # of bonded electron groups on the central atom (n) # of lone pairs on the central atom (m) total # of electron groups on central atom (n + m) Name of the hape of the Molecule 2 E linear 3 E trigonal planar 2 E E tetrahedral 3 E trigonal pyramidal 2 E

8 2. or the following molecules: a) draw the molecule following the octet rule b) determine the E notation for the shape of the molecule c) name the shape of the molecule Drawing of Molecule E Notation (nem) Name of hape N 2 E 0 linear i 2 E 0 linear l l 3 E 0 trigonal planar N 2 E 1 3 E 1 trigonal pyramidal N 2 E 1 2 E 2 l l 4 E 0 tetrahedral l s 3 E 1 trigonal pyramidal e 2 E 2

9 nswers to omework: lassifying Bonds and the Bonding ontinuum 1. Read over this note very carefully. 2. or the following bonds: a) calculate the difference in electronegativity ( EN) between the bonding atoms b) determine the type of bonding that will occur: non-polar, polar or ionic if the bond is non-polar, it is uncharged so do not draw in any charged regions if the bond is polar, label the appropriate atoms with partial positive () and partial negative ( ) charges if the bond is ionic, label the appropriate atoms with full positive (+) and full negative ( ) charges δ Na Mg EN= = 1.24 polar bond, so draw in partial charges EN= = 2.03 ionic bond, so draw in full + and charges EN= = 2.13 ionic bond, so draw in full + and charges EN= = 1.43 polar bond, so draw in partial charges N B l EN= = 0.38 non-polar covalent bond, do not draw any charges EN= = 0.40 non-polar covalent bond, do not draw any charges EN= = 0.01 non-polar covalent bond, do not draw any charges EN= = 1.12 polar covalent bond, so draw in partial charges + K l e EN= = 2.34 ionic bond, so draw in full + and charges EN= = 0.35 non-polar covalent bond, do not draw any charges 3. Give three examples of bonds for which EN = 0.0. EN= = 1.43 polar covalent bond, so draw in partial charges EN= = 0.03 non-polar covalent bond, do not draw any charges ny bond between atoms of the same element will have EN = 0.0, for example,,,, and any of the other Nl elements, or bonds etc. Do not use metal metal as your example, because two metal atoms do not bond in this way. 4. or the following molecules, determine the type of bond(s) and label any partial or full charges. ydrogen cyanide (a poisonous gas) N Dihydrogen Monoxide (water) 2 N EN = = 0.35 non-polar bond EN N = = 0.49 non-polar bond EN= = 1.24 polar bond, so draw in partial charges no polar bonds, so do not draw in any charges

10 Methanol (a poisonous alcohol) 3 ormic cid (in red ant stings) EN = = 0.35 non-polar, no charges EN = = 0.89 polar, partial charges EN = = 1.24 polar, partial charges EN = = 0.35 non-polar, no charges EN = = 0.89 polar, partial charges EN = = 1.24 polar, partial charges

11 ractice Determining the olarity of Molecules omework: Draw stick diagrams for the compounds below. Determine the overall polarity of each molecule. Label any charges. N N 2 l 2 N sl 3 Drawing of Molecule N E Notation and Name of hape 3 E 1 trigonal pyramidal 2 E 2 4 E 0 tetrahedral asymmetrical shape olarity of Molecule polar bonds ( EN = 0.84) very polar molecule asymmetrical shape polar bonds ( EN = 1.40) very polar molecule symmetrical shape asymmetrical atoms non-polar bonds ( EN = 0.41, 0.11) slightly polar molecule (don t draw charges) N 2 E 0 linear 3 E 0 trigonal planar symmetrical shape asymmetrical atoms non-polar bonds ( EN = 0.35, 0.49) slightly polar molecule (don t draw charges) symmetrical shape asymmetrical atoms polar bonds ( EN = 0.03, 1.43) very polar molecule l N l s l l 2 E 1 2 E 0 linear 2 E 1 3 E 1 trigonal pyramidal asymmetrical shape asymmetrical atoms polar bonds ( EN = 1.25, 0.97) very polar molecule symmetrical shape symmetrical atoms non-polar bonds ( EN = 0.03) non-polar molecule asymmetrical shape asymmetrical atoms non-polar bonds ( EN = 0.46, 0.38) slightly polar molecule (don t draw charges) asymmetrical shape polar bonds ( EN = 1.00) very polar molecule