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Chapter 7

Chapter 7. Ionic and Covalent Bonds. Review. Chemical Bonds form between 2 or more atoms to form molecules Two types of chemical bonds: Ionic Bonds & Covalent Bonds. Ionic Bonds & Covalent Bonds. Ionic Bonds- Electrons are transferred between a metal and a non-metal

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Chapter 7

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  1. Chapter 7 Ionic and Covalent Bonds

  2. Review Chemical Bonds form between 2 or more atoms to form molecules Two types of chemical bonds: Ionic Bonds & Covalent Bonds

  3. Ionic Bonds & Covalent Bonds • Ionic Bonds- Electrons are transferred between a metal and a non-metal • Covalent Bonds- Electrons are shared between two non-metals • Remember: The “stairs” on your periodic table separate the metals and non-metals

  4. In this Chapter… • You will understand HOW and WHY Ionic and Covalent Bonds form • To start- remember that an element becomes stable with 8 Valence Electrons • Hydrogen and Helium are exceptions, they only need 2 to be full • Atoms will give, take, or share electrons to get to 8 Valence Electrons

  5. Electronegativity • Ability of an atom to gain an electron.

  6. Electronegativity • When two atoms have a big difference in electronegativity the electron gets transferred • When there is a small difference the atoms share the electron • This is WHY the atoms form the type of bonds that they do

  7. Ionic Bonds • Form between a metal and a non-metal • There’s usually a big difference in electronegativity, which causes the metal to give its electrons to the non-metal Example: K and O (3.5 - .8 = 2.7 difference) • They transfer enough electrons so that both the metal and non-metal have 8 Valence Electrons

  8. Ions When atoms give or take electrons they become charged Ions • Metals lose electrons to become cations (+) • Non-metals gain electrons to become anions(-) Opposite charges attract, ions come together to form neutral molecules

  9. Ion Formation • To figure out what ion an element will form: • If it is a metal: Find out the number of valence electrons it needs to LOSE to get to zero. • Many Transition Metals can form more than 1 Ion • If it is a non-metal: Find out the number of valence electrons it needs to GAIN to get to 8 • Hydrogen can both lose and gain 1 electron

  10. Practice For each element, find out the ion that it forms Chlorine: Beryllium: Argon:

  11. Simple Ion Nomenclature (naming) • Simple cations are named by saying the element and adding the word “ion.” • Na+ is called “sodium ion” • Mg2+ is called “magnesium ion” • Simple anions are named by dropping the ending off the element name and adding “ide.” • F-is called “fluoride” • O2-is called “oxide” • N3-is called “nitride”

  12. Practice For each element, name the ion that it forms Chlorine: Beryllium: Argon:

  13. Ionic and Covalent BondsDay 2

  14. Ions Shortcut Pull out your periodic tables! Group 1 = 1+ Group 2 = 2+ Group 13 = 3+ Group 14 = 4+ or 4- ***Depends on what it bonds with Group 15 = 3- Group 16 = 2- Group 17 = 1-

  15. Simple Ionic Compounds Ions come together to form neutral compounds Today we will learn how to: • Write the chemical formula of the compound created • Figure out the name for the compound

  16. Chemical Formulas of Ionic Compounds With the criss-cross method you use the charge of the cation to figure out the subscript of the anion and vice versa We write chemical formulas of ionic compounds using the criss-cross method

  17. Criss - Cross Method When possible, reduce the subscripts to get the most simple version of the chemical formula Situation 1: Ions with the same charge Mg2+ and O2- would be written as MgO, NOT Mg2O2 Situation 2: Any subscript with a 1 Mg2+ and Cl- would be written as MgCl2 NOT Mg1Cl2

  18. Naming Ionic Compounds • When naming ionic compounds, simply write the element name of the metal followed by the ionname of the nonmetal. • The metal ion (cation) is always written first • The name of the metal is capitalized while the ion of the non-metal is not • NaClis called “Sodium chloride” • CaCl2is called “Calcium chloride”

  19. Practice Mg 2+ and Br - form what compound? Al 3+ and O2- form what compound?

  20. Ionic Bonding Day 2.5

  21. Today • Mini-quiz: How to find Ions • Review how to write formulas for Ionic Compounds • Discuss how to name Ionic Compounds • WHY Ionic Bonds form the compounds they do • HW: Ionic Bonding WS

  22. Mini-Quiz: Take out a half sheet of paper and your periodic table What Ions do the following elements form? S Li Al Ne Br

  23. Naming Ionic Compounds Use the “Criss-Cross” Method to write ionic compounds: • If the charges have the same number, you do NOT write the subscript • If the number is a 1, you do NOT write the subscript

  24. Practice- Take out your worksheet from yesterday 1. Na and Br: Na+ and Br- so NaBr 2. Ca and Cl Ca2+ and Cl- so CaCl2 3. Mg and S Mg2+ and S2- so MgS Try #4 Al and O and #5 Li and P

  25. Naming Ionic Compounds • When naming ionic compounds, write the element name of the metal followed by the ionname of the nonmetal. • NaCl is called “Sodium chloride” • CaCl2 is called “Calcium chloride”

  26. Practice 11. K and O 12. Mg and I 13. Al and Cl Try #14 Ca and Br and #15 Na and N on your own!

  27. Ionic Bonds Day 3Polyatomic Ions

  28. Polyatomic Ions • A polyatomic ion is made up of 2 or more atoms that are covalently bonded, but have an overall charge • Even though they are multiple atoms, we treat it like 1 ion A list of polyatomic ions with their charges is given on your reference sheet– you need to keep this safe!

  29. Polyatomic Ions in Formulas • Still use the same criss-cross method • Since the subscript applies to the ENTIRE polyatomic ion, the ion goes in ( ) with the subscript on the outside Example: Mg and OH Mg2+ and OH- form Mg(OH)2

  30. Practice writing formulas K and SO4 Al and NO3 NH4 and Cl

  31. Naming polyatomic ions Look up the name of the polyatomic ion using the polyatomic reference sheet The regular ion uses the same naming as usual • Full name for Cation (+) • -ide ending for Anion (-) Examples: Mg and OH Magnesium Hydroxide Na and MnO4 Sodium Permanganate

  32. Practice Naming K and SO4 Al and NO3 NH4 and Cl

  33. Ionic Bonding Day 4Transition Metals

  34. Transition Metals Even though transition metals technically have 2 valence electrons, they don’t act like it Transition Metals can form a wide variety of cations We will use our reference sheet to see what ions the various transition metals can form

  35. Figuring out transition metal charge If the ion that goes with the metal does NOT have a subscript, then the metal has the same charge as the other ion AuCl = Au+ because Cl-FeO = Fe2+ because O-2 If the ion that goes with the metal DOES have a subscript, then the metal has the ion charge of the subscript AuCl3 = Au3+ Fe2O3 = Fe3+

  36. Practice • What is the charge on Zn in ZnCl2? • What is the charge on Cr in CrO? • What is the charge on Co in CoBr3? • What is the charge on Ni in NiSO4?

  37. Figuring out ion charge without the formula Without the formula given, you cannot know which ion charge to use (when there is more than one choice) When the formula is not given, you must write the formula for all possible ion choices Example: What is the formula for Cu and Cl? CuCland CuCl2 are both the correct answer, you need both!

  38. Practice What are the possible formulas for… Fe and N? Ag and Br? Au and O?

  39. Naming Transition Metals Two types of names- standard and common name Standard name: Regular metal name with the ion number in roman numerals in parenthesis Example: Fe2+ Iron (II) Common name: Based on Latin Names Example: Fe2+ Ferrous Both are found on your transition metals reference sheet!

  40. Practice Name CuCl2with both the standard and common names Name AuCl and AuCl3 with their standard names

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