BRN: What do you see?

Bonding New section in table of contents

What is an ionic compound?  KC 1: An ionic compound consists of a metal and a non-metal bound together in a lattice structure by ionic bonds  KC 2: An ionic compound = metal + nonmetal Or cation + anion  KC 1: An ionic compound consists of a metal and a non-metal bound together in a lattice structure by ionic bonds  KC 2: An ionic compound = metal + nonmetal Or cation + anion

Ionic Compounds

 KC 3: Cation – positively charged ion  KC 4: Anion – negatively charged ion  Polyatomic Ions  “Poly” = many  “atomic” = atoms  Ion = charged  KC 5: Polyatomic ion = many atoms bonded together having an overall charge  See periodic table  KC 3: Cation – positively charged ion  KC 4: Anion – negatively charged ion  Polyatomic Ions  “Poly” = many  “atomic” = atoms  Ion = charged  KC 5: Polyatomic ion = many atoms bonded together having an overall charge  See periodic table

Ionic Bonding  KC 6: Ionic Bond – bond formed through electrostatic attraction between 2 oppositely charged ions  Review: What is an ion?  Different number of electrons from protons  Not a neutral atom  Contains a charge  KC 6: Ionic Bond – bond formed through electrostatic attraction between 2 oppositely charged ions  Review: What is an ion?  Different number of electrons from protons  Not a neutral atom  Contains a charge

 Ionic bond is formed through electrostatic attraction between 2 oppositely charged ions  These ions are attracted to one another and form what is called a lattice or crystalline structure  Ionic bond is formed through electrostatic attraction between 2 oppositely charged ions  These ions are attracted to one another and form what is called a lattice or crystalline structure Ionic Bonding

8 is the magic number!  KC 7: All atoms are trying to reach a valence shell of 8 – like a noble gas  KC 8: If this cannot be achieved easily, an atom will lose electrons to have a valence shell of zero  KC 7: All atoms are trying to reach a valence shell of 8 – like a noble gas  KC 8: If this cannot be achieved easily, an atom will lose electrons to have a valence shell of zero

Ionic Bonding  Each atom forms a charge that is related to its number of valence electrons  Example: calcium – 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2  2 valence electrons  8 is the magic number!  Is it easier to gain 6 or lose 2?  Each atom forms a charge that is related to its number of valence electrons  Example: calcium – 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2  2 valence electrons  8 is the magic number!  Is it easier to gain 6 or lose 2?

Ionic Bonding

Covalent Compounds & Bonding  KC 9: Covalent compounds consist of 2 or more nonmetals bonded together  KC 10: A covalent bond is formed from the sharing of electrons  KC 9: Covalent compounds consist of 2 or more nonmetals bonded together  KC 10: A covalent bond is formed from the sharing of electrons

Ionic Bondvs.Covalent Bond

Naming Puzzle MetalCationChargeNonmetalAnionCharge Compound (Formula) Total charge Name Ca F

Naming Rules: If you need these for your reference, you can print them from my website We need to spend the class time practicing, not copying down the rules

Naming Ionic Compounds – formula to name Type A: Metal + Nonmetal Name the metal Name the nonmetal Change the nonmetal ending to “ide” Type B: Metal + Polyatomic Ion Name the metal Name the polyatomic ion Type C: Transition Metal + Nonmetal Name the transition metal Find the charge of the metal and place in roman numerals Name the nonmetal

Naming Ionic Compounds – formula to name Type A: Metal + Nonmetal Example: KCl Type B: Metal + Polyatomic Ion Example: Ca(NO3)2 Type C: Transition Metal + Nonmetal Example: FeF2

Creating Ionic Compounds – the switcheroo!  When bonding a metal and nonmetal in an ionic compound, the charges have to balance  To do this, you just switch the charges and cross them down: the switcheroo  Can also be done the opposite way to determine charges  When bonding a metal and nonmetal in an ionic compound, the charges have to balance  To do this, you just switch the charges and cross them down: the switcheroo  Can also be done the opposite way to determine charges

The Switcheroo!  Example: aluminum chloride

EXCEPTION ALERT!!  What if you do the switcheroo and the charge for a nonmetal does not come out correctly?

EXCEPTION ALERT!!  If the charge of the nonmetal comes out wrong, that means the charges have reduced To correct the charge, just multiply both charges by the necessary number to make it the charge that you know it is

Naming Ionic compounds - Name to formula Write the formula for the compound using subscripts Write the element symbol Determine the charge of each element from looking at the periodic table Do the switcheroo! Cross charges down

Naming Rules – name to formula  Example: copper (II) chloride

Covalent Compounds -formula to name Write the Greek prefix for the first element and name it 1 = mono6 = hexa 2 = di7 = hepta 3 = tri8 = octa 4 = tetra9 = nano 5 = penta10 = deca Write the prefix for the second element and name it

Naming Rules – Covalent Compounds  Example – NO 2  Example – dibromine hexaphosphide  Example – NO 2  Example – dibromine hexaphosphide

Bonding  KC 11: Some molecules are more stable when they are found as diatomic – two of the same element covalently bonded BrINClHOF

Bonding

KC 12: Lewis Structure Rules 1.Draw skeleton of molecule or compound and count total valence electrons able to use 2.Give all elements full octet and a single bond between elements. 3.Count number of electrons in drawing from step #2 and compare to number of electrons allowed 4.If too many, do the “move a pair lose a pair” rule until you have the correct number of electrons  Move electrons from outside in to form double or triple bond then erase a pair of electrons from the outside 1.Draw skeleton of molecule or compound and count total valence electrons able to use 2.Give all elements full octet and a single bond between elements. 3.Count number of electrons in drawing from step #2 and compare to number of electrons allowed 4.If too many, do the “move a pair lose a pair” rule until you have the correct number of electrons  Move electrons from outside in to form double or triple bond then erase a pair of electrons from the outside

 How many electrons does hydrogen have?  Will it be happy with 8?  NO!  KC 13: Hydrogen follows the duet rule – only needs 2 electrons to be happy  How many electrons does hydrogen have?  Will it be happy with 8?  NO!  KC 13: Hydrogen follows the duet rule – only needs 2 electrons to be happy EXCEPTION ALERT!!

Lewis Structure Rules 1.Draw skeleton of molecule or compound and count total number of valence electrons to use  Follows logic; place the element that is only contained once in the middle Example: CO 2 C = 4e - O = 6 x 2 = 12e - Total = 16e - 1.Draw skeleton of molecule or compound and count total number of valence electrons to use  Follows logic; place the element that is only contained once in the middle Example: CO 2 C = 4e - O = 6 x 2 = 12e - Total = 16e -

Lewis Structure Rules 2.Give all elements full octet (8 around each element) and a single bond between elements. Example: CO 2 16e - 2.Give all elements full octet (8 around each element) and a single bond between elements. Example: CO 2 16e -

Lewis Structure Rules 3. Count number of electrons in drawing from step #2 and compare to number of electrons allowed Example: CO 2 3. Count number of electrons in drawing from step #2 and compare to number of electrons allowed Example: CO 2

Lewis Structure Rules 4. If too many, do the move a pair lose a pair rule until you have the correct number of electrons  Move electrons from outside in to form double or triple bond then erase a pair of electrons from the outside Example: CO 2 **Cannot break octet rule!!** 4. If too many, do the move a pair lose a pair rule until you have the correct number of electrons  Move electrons from outside in to form double or triple bond then erase a pair of electrons from the outside Example: CO 2 **Cannot break octet rule!!**

Lewis Structure Rules  Most Lewis structures for compounds follow the common bonding patterns: 4 bonds3 bonds2 bonds1 bond 0 L.P.1 L.P.2 L.P.3L.P.  Most Lewis structures for compounds follow the common bonding patterns: 4 bonds3 bonds2 bonds1 bond 0 L.P.1 L.P.2 L.P.3L.P.

Bonds: Lone Pairs:

Shapes of Molecules  The Lewis structure can be transferred into a 3D model that tells us the exact shape, bond angles, and polarity of molecules

# of things # bonds # lone pairs Molecular geometry Bond angle Example 2 20linear180CO Trigonal planar 120BF 3 321Bent<120SO 2 440tetrahedral<109.5CH Trigonal pyramidal <109.5NH 3 422Bent<109.5H2OH2O

Polarity  KC 14: The shape of the molecule and the electronegativity of the elements determines the molecule’s polarity  We use vectors to represent polarity  Demonstration: H 2 O  KC 14: The shape of the molecule and the electronegativity of the elements determines the molecule’s polarity  We use vectors to represent polarity  Demonstration: H 2 O

Your turn!  You are going to be given a molecule to build and show to the class  You must include:  Name  Formula  Lewis structure  Molecular geometry  polarity  You are going to be given a molecule to build and show to the class  You must include:  Name  Formula  Lewis structure  Molecular geometry  polarity

Review Activity