E-Day #2 Chemistry Lesson
Valence Electrons & the Periodic Table
Name: ________________________________________
Date: ________________________ Period: _______
THIS ASSIGNMENT IS TO BE COMPLETED ON THE SNOW DAY AND DUE ON THE NEXT DAY WE RETURN
TO SCHOOL! (If you are truly unable to access this video due to technical difficulties, please bring a note
from your parent explaining the situation and stating WHEN you will have this assignment completed.)
Part I. Valence Electrons
Question: What are valence electrons? How can we determine the number of valence electrons of an
element by looking at the Periodic Table?
Find out! Search online for Tyler Dewitt’s You Tube video called: Valence Electrons & Periodic Table.
Pause the video along the way to answer the questions.
1. On the electron structure diagram below, label the energy levels and state the number of electrons that
can be held in each.
2. Fill in the appropriate number of electrons on the diagrams below for the elements in Group 1A.
Group 1A
3. What are valence electrons? _______________________________________________________________________________
4. What is the pattern of valence electrons for Group 1A atoms? _________________________________________
5. Draw the electron structure diagram for Potassium (element 19) here:
6. How many valence electrons does Potassium have? _______
7. Fill in the appropriate number of electrons on the diagrams below for the Group 2A elements.
Group 2A
8. Stop the video and draw the electron structure
diagram for Calcium (element 20) here:
9. How many valence electrons do ALL of the elements in Group 2A have? __________
10. Fill in the appropriate number of electrons on the diagrams below for the Group 3A elements.
Group 3A:
11. How many valence electrons do ALL the atoms of elements in Group 3A have? ________
12. Stop the video and draw the electron diagrams for atoms of the following elements beside each:
Group 4A
Group 5A
Group 6A
Group 7A
Group 8A
13. What is the pattern between A-Group number and number of valence electrons?
Part II: Lewis Dot Diagrams
Lewis Dot Diagrams are a short-cut way to draw valence electrons for various atoms. Simply write the
symbol for the element. Then, draw a dot on top, bottom, and either side to represent up to 4 valence
electrons. For 5-8 valence electrons, double up the dots in pairs on top, bottom and sides.
For example, Lewis Dot Diagram for Barium (Element 56 in Group 2A) is:
Dot diagram for Germanium (Element 32 in Group 4A) is:
Dot diagram for Iodine (Element in Group 7A) is:
14. Now, go back to Part I of this assignment and write the Lewis Dot Diagram next to the orbital structure
for each element.
Part III. Predicting Valence Electrons & Drawing Lewis Dot Diagrams
Use a periodic table to find each of the following elements. Then, indicate the number of valence electrons
and draw the Lewis Dot Diagram for each.
Strontium (Sr) element 38
Cesium (Cs) element 55
Selenium (Se) element 34
Lead (Pb) element 82
Indium (In) element 49
Antimony (Sb) element 51
Astatine (At) element 85
Radon (Rn) element 86
Bromine (Br) element 35
Francium (Fr) element 8
Xenon (Xe) element 54
Tellurium (Te) element 52