Presentation on theme: "NOMENCLATURE IONIC BONDING Thursday - Day 3 Notes."— Presentation transcript:
NOMENCLATURE IONIC BONDING Thursday - Day 3 Notes
VIDEO CLIPVIDEO CLIP ON HOW ATOMS BOND: IONIC COMPOUNDSON HOW ATOMS BOND: IONIC COMPOUNDS Click the link below to watch the video: http://www.nbclearn.com/portal/site/learn/chemistry -now/how-atoms-bond
Quick Review _Ions_____ - atoms that have lost or gained one or more electrons. __cation___ – positively charged ion _____anion___ – negatively charged ion The charge on the ion is known as the ___oxidation number____ __Polyatomic ion____ – ion consisting of two or more atoms
Practice - write the ion with the charge for the following elements * Li * Ca* H * Be * Si* K * Al * S* O * Na * Fr* N * F * Cl* P + 2+ 3+ + - 2+ + +-4 + + 3- 2- - 3-
NOTES #2: Binary Ionic Chemical Names and Formulas Ionic bonds are formed between a metal and a nonmetal OR cation + anion. The bond involves the transfer of electrons from the metal to the nonmetal. The electron is transferred from the cation to the anion so that both atoms have a complete valence shell (usually 8 electrons in valance). The overall charge of ionic compounds must equal zero.
Naming Ionic Compounds * First name the cation and then the anion. (metal) (nonmetal) * Change the ending of the anion to –ide. Example: MgCl 2 magnesium chloride Li 2 S_________________________ Lithium sulfide
Practice MgO _________________________ K 3 P ________________________ CsCl ________________________ Ba 3 N 2 ________________________ Magnesium oxide Potassium phosphide Cesium chloride Barium nitride
DRAWING Lewis Dot Structures for Ionic Compounds The overall charge on the compound must equal zero, that is, the number of electrons lost by one atom must equal the number of electrons gained by the other atom. The Lewis Structure (electron dot diagram) of each ion is used to construct the Lewis Structure (electron dot diagram) for the ionic compound. The Lewis Dot structures show the location of the valence electrons after the electrons have been transferred. Examples: Lithium fluoride Lithium atom loses one electron to form the cation Li+ Fluorine atom gains one electron to form the anion F- Lithium fluoride compound can be represented as Remember the Octet rule….
DRAWING Lewis Dot Structures for Ionic Compounds Draw the Lewis structure of Lithium oxide. What would be the chemical formula for this compound?
Writing Formulas for Binary Ionic Compounds When given two ions, __________________ the charges and make them the ___________________. Do NOT keep the +/- signs _______________ subscripts if possible This means we must reduce the subscripts if they have a common denominator. Example: Ca 4 F 8 Balance subscripts Reduce CaF 2
Writing Formulas for Binary Ionic Compounds Ex: a.Na +1 + Cl -1 NaCl (+1 + -1 = 0) b. Mg +2 + O -2 MgO * (+2 + -2 = 0) * Don’t write this Mg 2 O 2 because it must be reduced. **Sum of charges must equal zero. A. Using Balanced charges Method:B. Using the Crisscross method: Example: Li +1 O -2 Now, let’s use the name to write the chemical formula Name cation anion formula Lewis Dot Structure Lithium oxide _______ _______ _____________ Li +1 O -2 Li 2 O Li +1
Important Facts about Ionic Compounds We use subscripts to represent the number of each ion. Al 2 O 3 2 Aluminum Ions and 3 Oxide Ions
A. Using Balanced charges Method:B. Using the Crisscross method: Magnesium phosphide______ _______ ____________ Name cation anion formula Lewis Dot Structure Mg 2+ and P 3- Mg 2+ P 3- 6+ 6- = 0 Mg 2+ and P 3- Mg 3 S 2 Mg 2+ P 3- Mg 3 P 2 For example 2…Change it from Magnesium sulfide to Magnesium phosphide
Homework: Page 9 For added help: watch this videowatch this video And use your periodic table!!!!
Notes 3: Binary Ionic Compounds with Transition Metals (Multivalent cations) Multivalent Cations are found mostly in the group B elements. (the middle of the periodic table) These elements are also known as the Transition metals.
If your cation is a transition metal, then you must specify the charge with a Roman numeral. Example: Iron (III) Sulfide Just like the compounds we looked at yesterday, the sum of charges must equal zero. and we can still use the Criss-cross method when writing the chemical formula. Roman Numeral Charge I+1 II+2 III+3 IV+4 V+5 VI+6 VII+7 VIII+8
Writing & Naming Formulas with Roman Numerals Practice Cu+ S 2- Cu 2 S Mn 2+ O2-O2- MnO Sn 4+ F-F- SnF 4 I-I- Pb 2+ Lead II iodide O 2- Fe 3+ Iron III oxide Pb 4+ Lead IV oxide P 3- Co 3+ Cobalt III phosphide
Naming Ionic Compounds with Roman Numerals If there is a transition metal (B group element) present in the formula, you will need to include a roman numeral when you name the compound. So, which metals DO NOT require a roman numeral? Al 3+, Zn 2+, Cd 2+ and Ag +
Writing Multivalent Compounds HOMEWORK Complete page 11 REMEMBER: How can you determine the charge or roman numeral? You will have to work backwards. And Roman Numeral = Charge of the Metal
Polyatomic Ions A polyatomic ion are groups of atoms that behave as one unit. They are treated like single ions in formulas, but use parenthesis when more than one is used in a formula. NEVER change name or look of polyatomic. If you change the subscripts for any part of the polyatomic, then it is no longer that same polyatomic ion. Otherwise….use all the same rules for naming and writing compounds as with any other Binary Ionic compound. EX: NH 4 + is not the same as NH + CO 3 2- is not the same as CO 2 2- or CO 2-
Naming Ionic Compounds with Polyatomic Ions When you name a compound with a polyatomic ion, the polyatomic ion keeps its name. It is easy to identify a compound with a polyatomic ion because it will have more than 2 elements (more than 2 capital letters).
Polyatomic Ion Practice FormulaName Al +3 CO 3 -2 Ca +2 NO 3 -1 K +1 ClO 3 -1 Al 2 (CO 3 ) 3 Aluminum carbonate Ca(NO 3 ) 2 Calcium nitrate KClO 3 Potassium chlorate Question: How would potassium chlorite be different? K +1 ClO 2 -1 KClO 2
Name the following compounds Ba(OH) 2 Change CaSO4 to Cu CuSO 4 (NH 4 ) 3 P Barium hydroxide Copper II sulfate Ammonium phosphide
Write the formula for the following compounds: cationanionformula Strontium phosphate ________ _________ ______________ Lithium acetate ________ _________ ______________ Sodium sulfate _________ _________ ______________ Sr 2+ PO 4 3- Sr 3 (PO 4 ) 2 Li + C2H3O2-C2H3O2- LiC 2 H 3 O 2 Na + S0 4 2- Na 2 S0 4
Keys to Success Before naming ANY compound, Identify the type of compound. Molecular? Ionic? Acid? If it is molecular, remember to use your prefixes. If it is ionic, ask yourself. Does the metal need a roman numeral? Does it contain a polyatomic ion? If it is an acid, which pattern does it follow?
PUZZLE PIECE ACTIVITY ON WRITING FORMULAS FOR IONIC COMPOUNDS Work in pairs to assemble the various compounds. Let’s try the first one together. What is the compound formed between Mg and F? Mg 2+ Magnesium F - fluoride F - fluoride A perfectly assembled compound should be a square or a rectangle. Metal Metal’s Charge Nonmetal Nonmetal’s Charge Picture of Puzzle Pieces FormulaName Sum of Charges MgF +2MgF 2 magnesium fluoride 0