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Valence Electrons & Lewis Dot Structure Unit 3.4 The Atom.

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Presentation on theme: "Valence Electrons & Lewis Dot Structure Unit 3.4 The Atom."— Presentation transcript:

1 Valence Electrons & Lewis Dot Structure Unit 3.4 The Atom

2 Electron(s) in an atom’s highest occupied energy level – Outermost electrons of the electron cloud – Establish chemical characteristics of elements – Only electrons shown in Lewis electron dot structures Symbolized as dots Lewis Dot Structures Valence electrons

3 Lewis Structures Find out which group (column) your element is in. This will tell you the number of valence electrons your element has. You will only draw the valence electrons.

4 Groups - Review Each column is called a “group” Each element in a group has the same number of electrons in their outer orbital, also known as “shells”. Except for He, it has 2 electrons The electrons in the outer shell are called “valence electrons”

5 Number of valence electrons is the same as the group number for representative elements Lewis Dot Structures

6 Helium is an exception because its highest occupied energy level can only hold two electrons Lewis Dot Structures

7 Number of valence electrons determines behavior – Elements in the same group have similar chemical properties Lewis Dot Structures

8 Drawing an Electron Dot Structure Step 1 Step 2 Identify the symbol for the element and its number of valence electrons using the periodic table. Place the corresponding number of electron dots around the symbol. Imagine that the symbol has four sides: top, right, bottom, and left. Begin by assigning one dot per side, moving clockwise around the symbol. Then, if there are still more dots to assign, start adding a second dot to each side until all of the valence electrons have been accounted for.

9 Drawing an Electron Dot Structure Ex) Draw the electron dot structure for phosphorus. Identify the symbol for the element and its number of valence electrons using the periodic table. Place the corresponding number of electron dots around the symbol. Imagine that the symbol has four sides: top, right, bottom, and left. Begin by assigning one dot per side, moving clockwise around the symbol. Then, if there are still more dots to assign, start adding a second dot to each side until all of the valence electrons have been accounted for. Step 1 Step 2 Does the result make sense? The symbol for phosphorus is P. Phosphorus is in group 5A so it has 5 valence electrons. Yes.

10 Lewis Structures 1)Write the element symbol. 2)Carbon is in the 4 th group, so it has 4 valence electrons. 3)Starting at the right, draw 4 electrons, or dots, counter- clockwise around the element symbol.

11 Lewis Structures 1)Check your work. 2)Using your periodic table, check that Carbon is in the 4 th group. 3)You should have 4 total electrons, or dots, drawn in for Carbon.

12 Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

13 Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

14 Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

15 Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

16 Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

17 Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

18 Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

19 End of Study Guide. Complete the Lewis Structure Worksheet You should know how to draw Lewis Structures for the first 20 elements.

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