lewis structures. lewis dot diagrams show the valence electrons for an element. steps. 1. draw...
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Lewis Dot Diagrams
Show the valence electrons for an element.
Steps.1. Draw element Symbol2. Place the number of electrons around
the symbol. One dot per electron. Ex. Carbon
Steps for Lewis Structures
1. Add up total number of valence electrons.2. Draw a skeleton (Carbon, the solo element,
or the most electronegative element goes in the middle)★Hydrogen and the Halogens CANNOT be in the center.
3. Distribute the electrons as PAIRS. Start from the outside and move inward.
4. Count and adjust electrons till each element has 8. (except Hydrogen)
Polyatomics
Same as compounds but you must add/subtract the charge from the electrons in step 1.
And place the structure in brackets with the charge outside.
Ex. Hydroxide. How many electrons in a neutral OH?7 How many in OH-?8
VSEPR
Stands for “Valence shell Electron pair Repulsion”
V-Valence S-Shell E-Electron P-Pair R-Repulsion Basically Electrons don’t like each other
very much!
5 Shapes
Tetrahedral- four single bonds Trigonal Pyramidal- 3 single bonds and 1
lone pair Trigonal planar – 2 single, 1 double Bent- 2 bonds (any type) and lone pairs Linear- 2 bonds no lone pairs or just 2
atoms
PracticeDraw the Lewis structure and predict the shape
CF4
Tetrahedral
PH3
Trigonal Pyramidal
SO3
Trigonal Planar
H2O Bent
Predict the shape of the following PF3
Trigonal Pyrimidal
NO3-
Trigonal Planar
SO42-
Tetrahedral
SF2
Bent
SiO2
Linear
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