Naming Compounds
What's in a name? That which we call a rose By any other name would smell as sweet." - William Shakespeare, Romeo and Juliet (II, ii)
Background: valences and formulas • We can determine the formula of a compound by completing Lewis diagrams or via “valence” • Valence is “the number of electrons an atom must gain, lose, or share to complete its octet” • For representative elements valence starts at 1 (IA), climbs to 4 (IVA) and falls back to 1 (VIIA) • By knowing the valence of elements you can determine the formula of compounds • E.g. what compound would form from C + S? Step 1 - write valences: C4S2 Step 2 - cross down valences: C2S4 AlBrStep S- ZnO Mgformula: or2 Cu2O simplify 3 K23 3N2 CCl4 CuOCS a) Al,Br b) K,S c) Zn,O d) Mg,N e) C,Cl f) Cu,O
Ionic compounds (metal with 1 valence) • • • •
Rules for naming Names end in -ide. Example: sodium chloride Metal (+ve ion) comes 1st (not chorine sodide) Use the group valence for nonmetals Do not capitalized unless starting a sentence
Give formulae & name: Ca + I, O + Mg, Na + S = Ca2I1 = CaI2 = calcium iodide = Mg2O2 = MgO = magnesium oxide = Na1S2 = Na2S = sodium sulfide
Multiple valence: Latin naming • When the metal in an ionic compound is multivalent there are 2 methods: Latin or IUPAC • Latin is older (not useful for some compounds) • As before, the name ends in -ide & +ve is first • The metal is named with it’s Latin or English root and ends in -ic or –ous to denote valence • E.g. Cu1 is cuprous, E.g. Cu2 is cupric • Lower = ous, Higher = ic • Give formulas and Latin names for: Cu2 + Cl = Cu2Cl1 = CuCl2 = cupric chloride Co2 + Cl = Co2Cl1 = CoCl2 = cobaltous chloride • For latin naming: know rules, remember Hg is an exception, do not memorize Latin names
Element (valence)
English Latin Name Higher Lower name valence valence Metals that have and use latin names Cu (1,2) Copper Cuprum Cupric Cuprous Fe (2,3) Iron Ferrum Ferric Ferrous Pb (2,4) Lead Plumbum Plumbic Plumbous Sn (2,4) Tin Stannum Stannic Stannous Metals that do not have latin names Co (2,3) Cobalt Cobaltic Cobaltous Cr (2,3) Chromium Chromic Chromous Mn (2,3) Manganese Manganic Manganous Metals that have latin names but use english root Hg (1,2) Mercury Hydrargyrum Mercuric Mercurous
Multiple valence: IUPAC naming • Name ends in -ide, positive/metal comes first • The valence of the metal is indicated in brackets using roman numerals • E.g. Cu1 is copper(I), Cu2 is copper(II) • Numbers refer to valences not to #s of atoms • Try: Cu2+Cl, Zn2 + Cl, Co2+Cl, Hg+S (do both) Cu2+Cl = Cu2Cl1 = CuCl2 = copper(II) chloride Zn2+Cl = Zn2Cl1 = ZnCl2 = zinc chloride Co2+Cl = Co2Cl1 = CoCl2 = cobalt(II) chloride Hg+S = Hg1S2 = Hg2S = mercury(I) sulfide Hg+S = Hg2S2 = HgS = mercury(II) sulfide
Compounds containing polyatomic ions • So far we have given valences to single atoms Li1O2 Li2O Li + O • Groups of atoms can also have valences • “Polyatomic ions” are groups of atoms that interact as a single unit. For valence see p95. • E.g. OH1, (SO4)2. Ba3(PO4)2 = barium phosphate • Naming compounds with polyatomic ions is similar to naming other ionic compounds • You should note that compounds with polyatomic ions have names ending in -ate or -ite not -ide • Note that most are negative, except ammonium • Name: Ca(OH)2, CuSO4, NH4NO3, Co2(CO3)3
Compounds containing polyatomic ions Ca(OH)2 CuSO4 NH4NO3 Co2(CO3)3
- calcium hydroxide - copper(II) sulfate - ammonium nitrate - cobalt(III) carbonate
Naming covalent compounds 1 mono 2 di 3 tri 4 tetra 5 penta 6 hexa 7 hepta 8 octa 9 nona 10 deca
• -ide ending, each element has “prefix” • prefix refers to # of atoms - not valence N2O4 = dinitrogen tetroxide • Exception: drop mono for first element CO2 = carbon dioxide • The first vowel is often dropped to avoid the combination of “ao” or “oo”. CO = carbon monoxide (monooxide) P4O10= tetraphosphorus decoxide SO2= sulfur dioxide (doxide) • Name: CCl4, P2O3, IF7
Write and name the following covalent compounds (IUPAC) CCl4 carbon tetrachloride P2O3 diphosporus trioxide IF7 iodine heptafluoride For more lessons, visit www.chalkbored.com
BONDING REVIEW Directions: Each slide provides information in a question answer format. Click once to see the question and then again for the answer.
Bonds Between Atoms
Polyatomic Ions
Ionic Covalent
Molecular Substance
Metallic
Network Solids Polar Nonpolar
What are we going to learn about???
Coordinate Covalent
See if you can define the following words before starting the lesson…
• Anion- negative ion • Cation-positive ion • Octet Rule- rule that states that atoms tend to gain, lose, or share electrons so that each atom has full outermost energy level which is typically 8 electrons. • Polyatomic Ion- charged group of covalently bound atoms • Monatomic Ion- ion formed from a single atom • Molecule-neutral group of atoms united by covalent bonds • Alloy- homogeneous mixture of metals • Unshared Pair- pair of electrons that is not involved in bonding but instead is held exclusively by one atom.
Marriage Forming of a bond is like marriage •More stable •exothermic
Divorce •Less stable
•Endothermic
The breaking of a bond relates to a divorce.
Ionic Bonds •What is an Ionic Bond? - An Ionic Bond is a chemical bond resulting from the TRANSFER of electrons from one bonding atom to another • When is an ionic bond formed? - An ionic bond is formed when a cation (positive ion) transfers electrons to an anion (negative ion).
What are some characteristics of an ionic bond? 1. Crystalline at room temperatures 2. Have higher melting points and boiling points compared to covalent compounds 3. Conduct electrical current in molten or solution state but not in the solid state 4. Polar bonds
Covalent Bonds •What is an Covalent Bond? - A covalent bond is a chemical bond resulting from SHARING of electrons between 2 bonding atoms.
• What forms a covalent bond? - A covalent bond is formed between two nonmetals.
What are some characteristics of a covalent bond?
1. Covalent bonds have definite and predicable shapes. 2. Very strong 3. Low melting and boiling points
Covalent Bonds can have multiple bonds, so you should be familiar with the following… Single Covalent Bondchemical bond resulting from sharing of an electron pair between two atoms.
Double Covalent Bondchemical bond resulting from sharing of two electron pairs between two atoms. Triple Covalent Bondchemical bond resulting from sharing of three electron pairs between two atoms.
There are five different categories associated with covalent bonds. What are the 5 different categories?
Covalent
Molecular Substance
Network Solids Polar
Nonpolar
Coordinate Covalent
First, we are going to look at Polar Covalent… What is polar covalent?
-Polar covalent is a description of a c bond that has an uneven distribution of charge due to an unequal sharing of bonding electrons.
The boy is not equally sharing with anyone else but rather taking all the food for himself.
Next, we are going to look at Non-Polar Covalent… What is non-polar covalent? -Non polar covalent is a covalent bond that has an even distribution of charge due to an equal sharing of bonding electrons.
This couple is non- polar because they are sharing the drink equally between them.
Next, we are going to look at Molecular Substances… What is a molecular substance? -A molecular substance is a substance that has atoms held together by covalent bonds. Name 2 Characteristics of a Molecular Substance.
1. Weak 2. Low melting and boiling points
Next, we are going to look at Coordinate Covalent… What is a Coordinate Covalent Bond? -A coordinate covalent bond is a bond formed when one atom donates both electrons that are shared.
People donate their blood to help others just like atoms “donate” electrons to form stable octets.
*Think about the party analogy!
Now, we are going to look at Network Solids… What is a Network Solid? -A network solid is a solid that has covalently bonded atoms linked in one big network or one big macromolecule. Name 3 Characteristics of a Network Solid. 1. Poor conductors of heat and electricity 2. Hard / Strong 3. High melting and boiling points
Diphenylglycoluril assembles into a unique, twodimensional hydrogen bonding network in the solid state, while exhibiting a twisted molecular structure.
Metallic Bonding What is a Metallic Bond? - A metallic bond occurs in metals. A metal consists of positive ions surrounded by a “sea” of mobile electrons. This shows what a metallic bond might look like.
Name 4 Characteristics of a Metallic Bond. 1. Good conductors of heat and electricity 2. Great strength 3. Malleable and Ductile 4. Luster
Polyatomic Bonds Polyatomic ions usually have a charge because the collection of atoms has either gained an extra electron or else it has lost an electron.
What is a Polyatomic Bond? - A polyatomic bond is charged group of covalently bonded atoms. It is made up of more than one atom.
Linear Trigonal Planer
Trigonal Bipyramidal Tetrahedral
Octahedral
Just as a summary to what each bond looks like…
REVIEW Now that you have completed the review provided you may wish to practice for your test by answering the following regents questions. The question is presented in the same way that http://regentsprep.org/ does them. If you would like to get reasons to why your answers were incorrect you can find the explanations there. After you have gotten your answer, click the mouse and the right answer will show up.
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