Periodic Table Study Guide

1. Periodic Table Study Guide How to Draw Lewis Structures

2. Lewis Structures • Find your element on the periodic table. • Determine the number of valence electrons. • This is how many electrons you will draw.

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. www.chem4kids.com

4. Groups - Review Group 8 = 8 electrons Group 1 = 1 electron Except for He, it has 2 electrons Group 2 = 2 electrons • Each column is called a “group” 3,4,5,6,7 • Each element in a group has the same number of electrons in their outer orbital, also known as “shells”. • The electrons in the outer shell are called “valence electrons” www.chem4kids.com

5. Location of valence electrons in a Lewis Dot Structure • How many total electrons can exist in the valence shell of H and He? • How about Li and heavier? • Follow my lead!

6. Lewis Dot Structures: Group 2A Example: Beryllium Write the element symbol. Beryllium is in the 2nd group, so it has 2 valence electrons. Starting at the right, draw 2 electrons (or dots). What other elements have the same Lewis Dot Structure? Why? Be

7. Lewis Dot Structures: Group 3A Example: Boron Check your work. Using your periodic table, check that Boron is in the 3rd group. You should have 3 total electrons, or dots, drawn in for Boron. B

8. Lewis Dot Structures: Group 5A Example: Nitrogen On your worksheet, try these elements on your own: H P Ca Ar Cl Al N

9. Lewis Structures On your worksheet, try these elements on your own: • H • P • Ca • Ar • Cl • Al H

10. Lewis Structures On your worksheet, try these elements on your own: • H • P • Ca • Ar • Cl • Al P

11. Lewis Dot Structures On your worksheet, try these elements on your own: • H • P • Ca • Ar • Cl • Al Ca

12. Lewis Structures On your worksheet, try these elements on your own: • H • P • Ca • Ar • Cl • Al Ar

13. Lewis Structures On your worksheet, try these elements on your own: • H • P • Ca • Ar • Cl • Al Cl

14. Lewis Structures On your worksheet, try these elements on your own: • H • P • Ca • Ar • Cl • Al Al

15. Lewis Dot Structures – Carbon Family • The elements in the Carbon family are unique • The stability of a an atom in the carbon family is special. • Hund’s Rule: An atom with a half filled shell is more stable than a partially filled shell. • This goes back to the electron configuration of Carbon. • 6 total electrons What you were told to do: ___ ___ ___ ___ ___ 1s 2s 2p What actually happens: ___ ___ ___ ___ ___ 1s 2s 2p Unstable stable

16. Lewis Dot Structure for Carbon Family C

17. Bohr Model of First 20 elements

18. Complete the Lewis Structure Worksheet You should know how to draw Lewis Structures for the first 20 elements.

19. Ionic Charge Atoms that gain or lose electrons become ions. • Atoms with low electronegativity will lose electrons • Example: Metals • Atoms with high electronegativity will gain electrons • Example: Nonmetals An atom will gain or lose electrons to become more stable by having a full valence shell – “The octet rule” • Ionic charge is the net electric charge that an atom will have after it gains/loses electrons to have a full valence shell.

20. Label the following as atoms or ions

21. Net Charges What is the net charge of this atom? What is the net charge of these ions?

22. Ionic Charges of the Representative Elements

23. Ion Representation Cations Anions An anion is formed when an atom gains an electron The anion has more electrons than protons So it has a net negative charge. Example:Fluorine atom to Fluorine ion F  Fill in the electrons and show the gained electron with another symbol • A cation is formed when an atom gives an electron. • The cation has more protons than electrons • So it has a net positive charge. Example: Sodium atom to Sodium IonNa 

24. Practice: Ionic Charge Directions Examples: Magnesium Phosphorus • Draw the Lewis dot structure • Show electrons that are gained or lost • Determine ionic charge • Represent as an ion

26. Review Questions: • Ionic bonds occur between __________ and __________. • When atoms lose electrons they gain a ______ charge. • When atoms gain electrons they gain a ______ charge. • Atoms that gain or lose electrons are called ________. • An ionic bond occurs when atoms ______ or ________ electrons.

27. Chemical Bonding Ionic Bonding (form salts) Covalent Bonding (form molecules) Covalent Bonds: http://www.youtube.com/watch?v=0mUncUj55FI Naming Covalent Bonds: http://www.youtube.com/watch?v=VokWJy_jpAc Ionic Bonds: http://www.youtube.com/watch?v=T40sM8-SXso Naming Ionic Bonds http://www.youtube.com/watch?v=7Lfc6jjp1WQ Bonding: http://www.youtube.com/watch?v=QqjcCvzWwww

28. Example of 1:1 ratio: Ionic bonds Salt: Li + F 

29. Practice: Ionic Bond formulas Reaction Name K + Cl Na + I 

30. Example of 1:2 ratio: Ionic bonds Salt Ca + C 

31. Practice: Reaction Name Mg + Cl Na + S 

32. Example of 1:3 ratio: Ionic bonds Salt Ga + I 

33. Example of 3:2 Ratio: Ionic Bonds

35. Name

36. Covalent Bonding Covalent Bond Covalent Bonding Covalent Bonds: http://www.youtube.com/watch?v=0mUncUj55FI Naming Covalent Bonds: http://www.youtube.com/watch?v=VokWJy_jpAc • A bond formed when atoms share one or more pairs of electrons • Compounds that are made of molecules have covalent bonds • Covalent bonds usually form between two non-metals.

37. Now, Read The Bare Essentials of Polarity comic strip and answer the questions on the question guide.

38. Molecular Polarity Non polar Polar (dipole molecules) When electrons are not equally attracted to the positive nucleus of each atom the bond is POLAR. The molecules will have oppositely charged ends (called poles) Example: Water • When electrons are equally attracted to the positive nucleus of each atom the bond is NON-POLAR • The molecule will not have charged ends (called poles) • Example: Diatomic molecules

39. Electronegativity nonpolar covalent, polar covalent, and ionic bonds • http://www.youtube.com/watch?v=Kj3o0XvhVqQ

40. Polar vs. Nonpolar Molecules

41. Polar Molecules: Water

42. Polar molecules: water

43. The Role of Electronegativity Remember: The electronegativity of an atom is its attraction for another atoms valence electrons. Brightstorm video: http://www.youtube.com/watch?v=un93VJxUfPA

44. Covalent BondingDiatomic Molecule: Single Bond (nonpolar)

45. Covalent BodingDiatomic Molecules: Double Bond (Nonpolar)

46. Covalent BondingDiatomic molecule: Triple Bond (nonpolar)

49. Circle the Full valence shell of electrons How many total bonds? Are these bonds polar or nonpolar? Indicate the single, double and triple bonds. How many total electrons are being shared?

50. Lewis dot Structure and Formula for a Covalent Bond Circle the valence electrons for each