1. Ionic & Molecular Compounds

2. Valence Electrons Susan Baird Dori Delaney Cindy Rothwell Return to Home Page

3. Ionic & Molecular Compounds Valence Electrons Valence electrons are the electrons in the outermost energy shell. Return to Home Page

4. Ionic & Molecular Compounds Valence Electrons Valence electrons are the electrons in the outermost energy shell. The number of valence electrons equals the A Group number for the element on the periodic table. Return to Home Page

5. Ionic & Molecular Compounds Valence Electrons Examine the Periodic TablePeriodic Table Return to Home Page

6. Ionic & Molecular Compounds Valence Electrons Examine the Periodic TablePeriodic Table Did you notice that the group numbers are labeled with two different sets of numbers? Return to Home Page

7. Ionic & Molecular Compounds Valence Electrons Examine the Periodic TablePeriodic Table Did you notice that the group numbers are labeled with two different sets of numbers? The upper numbers from 1 to 18 are the IUPAC Group numbers. Return to Home Page

8. Ionic & Molecular Compounds Valence Electrons Examine the Periodic TablePeriodic Table Did you notice that the group numbers are labeled with two different sets of numbers? The upper numbers from 1 to 18 are the IUPAC Group numbers. The lower numbers from 1A to 8A are the Main Group Numbers. Return to Home Page

9. Ionic & Molecular Compounds Valence Electrons Group 1A Group 6A Group 7A Group 8A Li O F Ne 1 valence 6 valence 7 valence 8 valence electron electrons electrons electrons Return to Home Page

10. Ionic & Molecular Compounds Valence Electrons Let’s try an example: How many valence electrons does carbon have? Examine the periodic table and find Carbon’s Main Group number.periodic table Return to Home Page

11. Ionic & Molecular Compounds Valence Electrons Let’s try an example: How many valence electrons does carbon have? Examine the periodic table and find Carbon’s Main Group number.periodic table Carbon is in Group 4A. Therefore carbon has 4 valence electrons. Return to Home Page

12. Ionic & Molecular Compounds Valence Electrons Now it’s your turn: periodic tableperiodic table How many valence electrons do each of the following elements contain? K S Al Br Answers are on the next page. Return to Home Page

13. Ionic & Molecular Compounds Valence Electrons Answers: periodic tableperiodic table How many valence electrons do each of the following elements contain? K is in Group 1A so it has 1 valence e -. S is in Group 6A so it has 6 valence e -. Al is in Group 3A so it has 3 valence e -. Br is in Group 7A so it has 7 valence e -. Return to Home Page

14. Ionic & Molecular Compounds Valence Electrons When elements form bonds with other elements they gain, lose or share electrons to obtain a full valence shell. Return to Home Page

15. Ionic & Molecular Compounds Valence Electrons When elements form bonds with other elements they gain, lose or share electrons to obtain a full valence shell. An element with a full valence shell is in its most stable form. Return to Home Page

16. Ionic & Molecular Compounds Valence Electrons A full valence shell consists of 8 electrons for most elements. Return to Home Page

17. Ionic & Molecular Compounds Valence Electrons A full valence shell consists of 8 electrons for most elements. The Octet Rule states that atoms gain, lose or share electrons to obtain 8 valence electrons. Return to Home Page

18. Ionic & Molecular Compounds Valence Electrons Most atoms follow the octet rule. Return to Home Page

19. Ionic & Molecular Compounds Valence Electrons Most atoms follow the octet rule. Hydrogen and Helium are two exceptions. Return to Home Page

20. Ionic & Molecular Compounds Valence Electrons Most atoms follow the octet rule. Hydrogen and Helium are two exceptions. The first shell of electrons is so small that it can only hold two electrons. Return to Home Page

21. Ionic & Molecular Compounds Valence Electrons Most atoms follow the octet rule. Hydrogen and Helium are two exceptions. The first shell of electrons is so small that it can only hold two electrons. Therefore H gains, loses or shares one electron to have a full (or empty) valence shell. Return to Home Page

22. Ionic & Molecular Compounds Valence Electrons Watch this video to see how valence electrons are involved in bonding.video Return to Home Page

23. Ionic & Molecular Compounds Valence Electrons To discover more about the role that valence electrons play in bond formation go to the Ionic Bonding or Covalent Bonding pages.Ionic Bonding Covalent Bonding To see how valence electrons are represented in short hand notation go to the Lewis Dot Structure page.Lewis Dot Structure Return to Home Page