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ELECTRON DOT FORMULAS—HOW DO THEY WORK?. (also known as Lewis dot structures). Why do we need electron dot formulas?. Once we have the electron dot formula, we can figure out how to bond one element to another. We can determine the type of bond that will form.
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ELECTRON DOT FORMULAS—HOW DO THEY WORK? (also known as Lewis dot structures)
Why do we need electron dot formulas? • Once we have the electron dot formula, we can figure out how to bond one element to another. • We can determine the type of bond that will form. • We can then predict how the bonded substances will behave.
Learning Goal • Be able to write the electron (Lewis) dot structure for any representative element.
THE “DOT” • 1) Represents an electron • 2) Specifically valence electrons (electrons in the outermost shell) LG: Be able to write the electron (Lewis) dot structure for any representative element.
LG: Be able to write the electron (Lewis) dot structure for any representative element. #1. Cs C I
LG: Be able to write the electron (Lewis) dot structure for any representative element. #2. S Ca B Guess: #3 Sr Cl Xe
LG: Be able to write the electron (Lewis) dot structure for any representative element. Guess: #4. O Ba N Guess: #5 Kr Mg P
LG: Be able to write the electron (Lewis) dot structure for any representative element. What are the rules? • 1)Number of dots = last digit of group # • 2) Order of dots: • 3) Why this order? first 2 are “s” electrons; next 6 are “p” electrons: 2 1 X 3 8 6 5 7 4 6 3 4 7 8 2 5 1
LG: Be able to write the electron (Lewis) dot structure for any representative element. Guess: #6. F Al Si Guess: #7 Ar Be Na
LG: Be able to write the electron (Lewis) dot structure for any representative element. - 2- - OK, so you think you have it?Try these: Guess#8 Cl- Br- S2- Cl Br S
LG: Be able to write the electron (Lewis) dot structure for any representative element. 2- 3- Just one more: Guess #9 O2- N3- Si4+ 4+ O N Si
LG: Be able to write the electron (Lewis) dot structure for any representative element. What are the rules for ions? • 1)Add or subtract the appropriate number of electrons • 2)Placebracketsaround the Lewis dot structure • 3)Write ion’s chargein the upper right hand corner
LG: Be able to write the electron (Lewis) dot structure for any representative element. Octet Rule • Notice there’s a trend for forming ions • The octet rule states that atoms will form ions by gaining or losing electronsso they will have a “full” valenceshell of 8 (octet) electrons just like a noble gas • Exception: The duet rule is for hydrogen and helium—they obtain a full valenceshell of 2 (duet) electrons