IPC 03B Chemical Bonding

Number of Valence Electrons Valence Electrons: Are electrons in the _________________________________________ The __________gases have _______ electrons.

Valence electrons are represented using ___________________________________. Valence electrons (dots) are placed around the _____________ sides of the element ___________. Electrons (dots) begin to __________________only when no more single spaces are left.

Octet Rule: atoms will _____________, ____________, or ________________ e- in order to have _____ valence e- and become _________________. Exception: the ___________ energy level only needs _____ valence electrons to be stable. So, ________ is stable and ___________ bond with other atoms.

Stable Atoms Atoms with ______________________valence electrons are ____________________________. Atoms with ____ valence electrons are __________________ Helium is stable with ___ electrons. Chlorine has _______ valence electrons (_________________) Chlorine _____________ an electron to have 8 valence electrons (____________________).

Are these elements stable? A neon atom is ________________ because it has an _________(8 valence e-). A sodium atom is ________________ because it has only ____ valence e-.

Stable atoms have ________________ valence shells. Lithium atoms have _______. Since the 1 st energy level only holds ________, lithium has ___ valence e-. If lithium __________ that electron, it will have a __________valence shell with 2 e- and an oxidation number of __________ Li Li +

Net Ionic Charges Metals will _________________electrons to form _________________________ ions. Nonmetals will __________ electrons to form _________________ ions.

Groups/Families Group NumberGroup NameValence ElectronsOxidation Number 1Alkali Metals1+1 2Alkaline Metals Transition Metals2Vary 13Boron Family3+3 14Carbon Family4 +/  4 15Nitrogen Family5 33 16Oxygen Family6 22 17Halogens7 11 18Noble Gases80

Chemical Bonds ______________________ are made up of more than one atom. When atoms combine to make molecules, they form ______________________. Types of Bonds:.

Ions: atoms with a ____________ (+) or _________________ (-) charge. Metals tend to _____________ electrons to form positive ions called _______________. Nonmetals tend to ____________ electrons to form negative ions called ____________.

Bond Formation:

No Ions!

6 Steps to Writing Ionic Compounds 1. Identify the (+) ion and the (  ) ion. 2. Write the symbols with their charges. 3. Cross  the charges. 4. Remove the charges. 5. Simplify the numbers. 6. Remove the “1”s and write the formula. 1. Magnesium Sulfide ______________ (+) ion _________ (  ) ion see periodic table Both #’s are divisible by 2. Metal first; then nonmetal.

Practice Steps Sodium Chloride Aluminum Sulfide 1. Identify the (+) ion and the (  ) ion. 2. Write the symbols with their charges. 3. Cross  the charges. 4. Remove the charges. 5. Simplify the numbers. 6. Remove the “1”s and write the formula. __________ (+) ion __________ (  ) ion _____________ (+) ion __________ (  ) ion

Reason: Total Charges = Zero Aluminum Sulfide Al 3+ S 2- Al 3+ S 2- Need 2 Al +3 ionsNeed 3 S -2 Ions

Polyatomic Ions (EOC)

Combining Atoms Positive ions must cancel the negative ions to make a neutral molecule. Ca 2+

Aluminum Sulfate Al 3+ Need 2 Al +3 ionsNeed 3 SO 4 -2 Ions Put ( )’s around the polyatomic ions so you don’t get the numbers confused.

Covalent Bonding in Action

Covalent Bonding Covalent Bond: ________________________ of electrons between two _______________________. Covalent compounds are called ________________________________________

Atoms ___________ electrons in order to get ______________ valence electrons. (Remember the Octet Rule) (Exception: only 2 e - for H)

Diatomic Elements 7 - Up Diatomic means “_____________” These 7 elements exist in ___________________ as diatomic molecules (covalently bond). H 2 (g) O 2 (g) F 2 (g) Br 2 (l) I 2 (s) N 2 (g) Cl 2 (g)

Greek Prefixes Don’t use prefix “mono” on the first element, only on the ______________. Certain vowel combinations are _________ allowed: oo and ao Ex. Don’t write tetraoxide; do write ________________. PrefixMeaning Mono-1 Di-2 Tri-3 Tetra-4 Penta-5 Hexa-6 Hepta-7 Octa-8 Nona-9 Deca-10

Naming Molecular Compounds 1) First Nonmetal: (Greek prefix + element name) 2) Second Nonmetal: (Greek prefix + element root + -ide ending)

Practice: 1. CCl 4 2. SO 3 3. N 2 O 4. P 2 O 5 5. CO 2 6. SF 6

Writing Molecular Compounds 1) nonmetal with nonmetal: Write the element symbol followed by the Greek prefix as a _________________________ for both elements.

Practice: 1. Dinitrogen tetroxide 2. Carbon monoxide 3. Sulfur dioxide 4. Phosphorus pentachloride

Type of Chemical Bond Ionic Bonds have ______________! _________________________________ Polyatomic ion & _____________________ Attraction between _________________ ions Covalent Bonds have _____________! _____________________________________ _______________________ of electrons

Metallic Bonds (free e-)

Metallic Bond The metal is held together by the ________________ of attraction between the positive nuclei of the metallic ________________and the “free floating” valence electrons known as a “___________________________”. Sea of Electrons