Determining Valence Electrons
The valence electrons are the electrons in the outermost electron shell.
Atoms that LOSE electrons are called ___________ and have an overall positive charge.
Atoms that GAIN electrons are called ___________ and have an overall negative charge.
Metals are LOSERS, Nonmetals are all about GAINS.
What separates the metals from the nonmetals on the Periodic Table?
To determine the element’s number of valence electrons, look at the last digit of the group number.
THIS DOES NOT WORK FOR THE TRANSITION METALS (Groups 3-12)
Example: Carbon is in group 4 and has ____ valence electrons.
1.
2.
3.
4.
5.
6.
7.
_________________ is the one Noble Gas (Group 18) that does not have 8 valence electrons.
fluorine _____
8. iodine _____
15. helium _____
lithium _____
9. silicon _____
16. hydrogen _____
phosphorus ___
10. oxygen _____
17. magnesium ____
francium _____
11. argon _____
18. xenon _____
calcium _____
12. barium _____
19. sulfur _____
carbon _____
13. potassium _____
20. boron _____
nitrogen _____
14. aluminum _____
21. bromine _____
REMEMBER: Atoms will take, share, or give away electrons so as to have _____ valence electrons.
22. Which groups on the periodic table want to lose electrons? What kind(s) of elements are these
groups?
23. Which groups on the periodic table want to gain electrons? What kind(s) of elements are these
groups?
24. Why do the elements from question 23 want to lose electrons? Why do the elements from question 24
want to gain electrons? (HINT: The answer is the same for both questions.).
25. How many valence electrons do the Alkaline Earth metals have? Are these elements very reactive?
Explain your answer.
26. What is the name of the atoms that lose electrons? What is their overall charge?
27. What is the name of the atoms that gain electrons? What is their overall charge?