Presentation on theme: "Developed By: Ms. Michelle Buroker Modified & Expanded By: Dr. Rick Moleski."— Presentation transcript:
Developed By: Ms. Michelle Buroker Modified & Expanded By: Dr. Rick Moleski
5 Types of Chemical Compounds (Based on Type of Bond) Binary ionic - metal ion – nonmetal ion Ternary ionic - at least one ion is a polyatomic ion (either cation or anion) Binary molecular - two nonmetals Binary acid - H +1 – nonmetal Ternary acid - H +1 – Polyatomic ion
STEP 1: Name the first ion (cation) If the first ion is a transition element other than zinc, cadmium, or silver, you must use a Roman Numeral with the name – we’ll discuss this later. You check the Periodic Table for the charge- Column 1 = 1 valence electron = +1 charge Column 2 = 2 valence electrons = +2 charge Column 13 = 3 valence electrons = + 3 charge STEP 2: Name the second ion (anion) changing the suffix to –ide.
Examples NaCl Name the metal element = cation Sodium Name the nonmetal by adding the suffix –ide to the root element name Chloride CaO CalciumOxide Al 2 S 3 AluminumSulfide MgI 2 MagnesiumIodide
What about the transition metals and using Roman Numerals? How does that work? Let’s see. FeO Notice – metal and nonmetal. Name the first ion. Since the first ion is a transition element, you must use a Roman Numeral to represent the charge. Exceptions Zn (+2) Ag (+1) Cd (+2) How do you know the charge? Deductive reasoning. All compounds are neutral. Oxygen has a -2 charge (Column 16, group 6A) Therefore ….. Iron must have a +2 charge since there is one iron and one oxygen. Iron gets a Roman Numeral II. Iron (II) Oxide
Cu 2 S Name the first ion. Since it is a transition metal, you must use a Roman Numeral. Which Roman Numeral? The Roman Numeral is the same as the charge of the ion. How do you find the charge? Deductive reasoning! All compounds are neutral Sulfur has a -2 charge (group 6A) There are two coppers. Therefore each copper must have a +1 charge for all ions to be neutral CopperI Sulfide
Another Example: MnO 2 Name the first ion. Since it is a transition metal, you must use a Roman Numeral. How do you determine the Roman Numeral? It is the same as the charge. What is the charge of Mn? All compounds are neutral. Oxygen (group 16) has a -2 charge. There are two oxygens and one Mn. Therefore Mn must have a +4 charge for this compound to be neutral. ManganeseIVoxide
So why must we use Roman Numerals with transition elements? single, definite charges or referred to as being monovalent The metals in groups 1A, 2A, and 3A have single, definite charges or referred to as being monovalent +1 Column 1, Group 1A metals have a +1 charge. +2 Column 2, Group 2A metals have a +2 charge. +3 Column 13, Group 3A metals have a +3 charge. Transition metals may have multiple charges – usually two different positive charges. They are referred to as being multivalent For example, there are two copper oxide compounds: Cu 2 O and CuO We can’t just say Copper oxide. Which one of these is Copper oxide? We must distinguish these by using a Roman Numeral which is which?
The solution lies with the negative ion or nonmetal’s charge which are always related back to the number of valence electrons and hence their oxidation number: Column 17, group 7A has a -1 charge (due to 7 valence e - ) Column 16, group 6A has a -2 charge (due to 6 valence e - ) Column 15, group 5A has a -3 charge (due to 5 valence e - ) Given CuO we know that there is a -2 charge per O atom and since there is only one O atom the total negative charge is -2 and must be offset by a +2 charge; because there is only copper atom it has to have a +2 charge or oxidation number giving us the name copper (II) oxide From a bonding perspective, the -2 charge of the O atom represents the acquisition of 2 electrons. These two electrons came from the copper atom and would represent the lose of 2 electrons
The other form of “copper oxide” has the formula Cu 2 O To determine its name we use the same approach: Oxygen has a -2 charge per atom and since there is only one atom the total negative charge is -2 (12 charge/ atom x 1 atom = -2) Therefore the offsetting positive charge has to have a total positive charge of +2 and since this charge is from 2 atoms of copper, each has a +1 charge (+2 total charge ÷ 2 atoms = +1 charge per atom) This gives us an charge or oxidation number of +1 and a Roman numeral of (I) Name: copper (I) oxide
There are three transition elements which do not require a Roman Numeral because they have single definite charges. Zinc – Zn +2 Cadmium – Cd +2 Silver – Ag +1 You need to remember the charges for these!!! Ag 2 OName the first ion. Silver Name the second ion changing the suffix to –ide. oxide ZnCl 2 Name the first ion. Name the second ion changing the suffix to –ide. Zincchloride No Roman Numerals needed for these.
The common names use the Latin derivative of the element’s name with a s uffix of either –ous or –ic. The –ous suffix name corresponds with the smaller charge. The –ic suffix name corresponds with the larger charge. With the traditional names using the different suffixes, you had to memorize both the name and the charges- not so with the Stock system since the Roman numeral tells you the charge. Remember Transition Metals named with Roman Numerals involve stock names.
Stock nameCommon Name Copper ICuprous Copper IICupric Iron IIFerrous Iron IIIFerric Lead (II)Plumbous Lead (IV)plumbic Some Examples
How do you write formulas for binary ionic compounds given the name? Three simple steps: 1.Write the symbol and charge of each ion 2.Balance the charges by adjusting number of ions 3.Based on the ratio apply the necessary subscripts Magnesium chlorideWrite the symbol and charge of each ion. You need a second Cl -1 to balance the charges The number of each ion (their ratio) tells you the subscripts for each Mg +2 Cl -1 Cl -1 MgCl 2 If only 1 atom then you omit that subscript
More examples: Iron (III) bromide Write the symbol and charge of each ion. The charge of the iron is provided by the Roman Numeral. Fe +3 Br -1 Balance the charges by adjusting the number of ions; this becomes the subscripts. The subscripts tell how many of each ion is needed to balance the compound. You’ll need three bromide ions to balance the charge (+3) of one iron (III) ion. Br -1 FeBr 3
Aluminum Sulfide Write the symbol and charge of each ion. Al +3 S -2 Balance the charges by supplying subscripts. In this case the charges do not evenly divide into each other. You must find the least common multiple (LCM). SIX How many aluminums are needed to arrive at a +6 charge? How many sulfurs are needed to arrive at a -6 charge? 2 3 Al +3 S -2 Al 2 S 3
These compounds contain at least one polyatomic ion. What is a polyatomic ion? Let’s look at the name to try to understand. It is an ion – that means it has a charge. It is polyatomic – that means it is made of more than one atom. Let’s look at some examples of polyatomic ions
CO 3 -2 carbonate This ion is composed of one carbon and three oxygens and the entire group has a charge of -2. Polyatomic ion – Group of covalently bonded atoms that carry an electrical charge and act as a unit during reactions, that is, the atoms stay bonded together. More examples: SO 4 -2 Sulfate SO 3 -2 Sulfite ClO 4 -1 Perchlorate ClO 3 -1 Chlorate ClO 2 -1 Chlorite ClO -1 Hypochlorite PO 4 -3 Phosphate C 2 H 3 O 2 -1 Acetate OH -1 Hydroxide NO 3 -1 Nitrate NO 2 -1 Nitrite You need to learn these!!! NH 4 +1 Ammonium MnO 4 -1 Permanganate
You see more than two element symbolized in the chemical formula Composed of two ions in which at least one is a polyatomic ion. There is only one common positive polyatomic ion, ammonium (NH 4 +1 ), that forms a compound
How do you name Ternary Ionic Compounds? EASY! PIECE OF CAKE! NO PROBLEM! 1) Name the first ion. 2) Name the second ion. Na 2 CO 3 Carbonate When you look at this compound you should recognize that this is NOT binary. There are THREE elements present. When you see this, immediately look for a polyatomic ion. Carbonate is present here. Name the first ion. Sodium Name the second ion. carbonate
A few more examples: Fe(OH) 3 step 1- Name the first ion. IronRemember that iron requires a Roman Numeral since it is a transition element. What Roman Numeral should be used? The Roman Numeral comes from the charge of the ion. How do you find the charge of the iron? You know two things: All compounds are neutral. You know the charge of OH (-1) Since there are 3 OH groups, each with a -1 charge, the charge of the iron must be +3 for the compound to be neutral (III) step 2- Name the polyatomic ion. hydroxide
NH 4 Cl step 1- Name the first ion. Ammonium step 2- Name the second ion. chloride Notice that since the second ion is a nonmetal as in binary ionic compounds, the suffix of the nonmetal changes to –ide. (NH 4 ) 3 PO 4 step 1- Name the first ion. step 2- Name the second ion. Ammoniumphosphate
ONE more example: Cu 2 SO 4 step 1- Name the first ion. Copper You should realize that you need a Roman Numeral since copper is a transition metal. The Roman Numeral is the same as the charge. What is the charge? Working backwards - the charge of sulfate is a -2 per polyatomic ion and there’s only 1 giving us a total of -2. The plus charge must offset the -2 giving us a total plus charge of+2 Since there are two coppers, the charge per copper ion must be +1. (I) sulfate step 2- Name the second ion.
How do you write formulas for Ternary Ionic Compounds? Very much like writing formulas for Binary Ionic Compounds. Three steps: Write the formulas/symbols of each ion. Balance the charges by adjusting the number of ions From the resulting ratio apply subscripts equal to the number of ions. If a subscript is needed for a polyatomic ion, it must be put in parentheses with the subscript on the outside.
Aluminum nitrateFirst, you can tell from the name that there is a polyatomic ion present (nitrate). Remember that all binary ionic compounds have suffixes of –ide. Write the formula/symbol and charge of each ion. Al +3 NO 3 -1 Balance the charges by adjusting the number of ions and those numbers (ratio) become the subscripts in the formula. Since Al is +3 and NO 3 is -1, you need a total of 3NO 3 -1 to balance one Al +3 You will need a subscript of 3 for NO 3 -1 ; you need to put this in parentheses with the 3 outside. Al(NO 3 ) 3
Lead (IV) acetateWrite the formula/symbol and charge of each ion. Pb +4 C 2 H 3 O 2 -1 Balance the charges by adjusting the number of ions and this number becomes the subscripts. Since Pb is +4 and C 2 H 3 O 2 is -1, you will need 4 C 2 H 3 O 2 -1 to balance 1Pb +4 Pb(C 2 H 3 O 2 ) 4 Calcium phosphate Write the formula/symbol and charge of each ion. Balance the charges to determine subscripts. Use the LCM of 6. Since Ca is +2 and PO 4 is a -3, you will need 3 Ca+2 to balance 2 PO 4 -3 Ca +2 PO 4 -3 Ca 3 (PO 4 ) 2
These compounds consist of two non- metals and to name them, you need to know the following prefixes: 1Mono- 2Di- 3Tri- 4Tetra- 5Penta- 6Hexa- 7Hepta- 8Octa- 9Nona- 10Deca-
1. The first nonmetal only gets a numeric prefix when there is more than one. No prefix if there is only one. 2. The second element always gets a numeric prefix and always has a suffix of -ide
CO 2 Carbon dioxide CO Carbon monoxide N2O4N2O4 Dinitrogen tetraoxide H2OH2O Dihydrogen monoxide CCl 4 Carbon tetrachloride Name the first element. Since there is only one, no prefix is needed. The second element always gets a prefix and a suffix of –ide. examples are CO 2 and CO Name the first element. Since there are two present, the prefix “di” is needed. The second element always gets a prefix and a suffix of –ide. examples are N 2 O 4 and H 2 O Why do we use the prefix tetra for the name of CCl 4 ?
Very easy to do!!! The prefixes tell you how to write the formulas. example diphosphorus pentoxide Remembering di = 2 and penta = 5, we get P 2 O 5 Notice that we drop the a from penta when adding to oxide
Silicon dioxide Diphosphorous pentachloride Silicon and oxygen are both nonmetals. The lack of a prefix on silicon means that there is only ONE silicon. The prefix “di” in front of oxide means that there are TWO oxygens. SiO 2 Phosphorous and chloride are both nonmetals. The prefix “di” means that there are TWO atoms of phosphorous covalently bonded to the chlorines The prefix “penta” before chlorine means that there are five chlorines. P 2 Cl 5
NO Nitrogen monoxide Nitrogen and oxygen are both nonmetals. The lack of a prefix on nitrogen means only ONE nitrogen. The prefix “mono” on oxygen indicates ONE oxygen. But wait these nonmetal molecular compounds can be written using the Stock System
Naming Molecular Compounds using the Stock System This system uses Roman Numerals that indicate the oxidation number of the first nonmetal in the formula. This is similar to what we did with the transition metals; for example P 2 O 5 step 1- we assign a charge value of -2 per Oxygen atom step 2- we calculate the total negative charge -2 x 5 = -10 step 3- we know that 2 phosphorus atoms contributed to an offsetting +10 giving us a +5 charge per P atom step 4- write the name of the first element followed by the Roman numeral for 5 in parenthesis step 5- use the –ide form of the second nonmetal’s name phosphorus (V) oxide
Writing Nonmetal Molecular Formulae using Stock System Since the name tells you the charge per atom of the first nonmetal, you follow these steps using sulfur (VI) oxide as our example: step 1- determine the charge of the second nonmetal from its position on the Periodic Table- -2 charge/O atom (column 17) step 2- figure out how many oxygen atoms are needed to equal a charge of -6 since you know that sulfur is a +6; 3 O step 3- from the ratio write the formula; 1S:3O = SO 3 Another example: phosphorus (V) oxide Let’s see what you can do
step 1- using the -2 oxidation number (charge) for an oxygen atom we know that it will not go into 5 as a whole number which is needed since atoms do not exist as fractional entities step 2- the remedy is to find the LCM (lowest common multiple) of both +5 (from the Roman numeral in the name) and -2 (found in the previous step) – lcm is found by multiplying the two charge numbers without regard for sign together 5 x 2 = 10 step 3- divide 10 by both charges resulting in the ratio of atoms P: 10 ÷ 5 = 2 O: 10 ÷ 2 = 5 Ratio 2P:5O step 4- write the formula using the ratio as the required subscripts P 2 O 5
Remember that acids always begin with an “H” in their formula and are aqueous solutions So, what is a binary acid? Binary Acids are those which contain hydrogen and a non-metal element. Naming them requires a prefix and a suffix added to the root of the nonmetal element and the word “acid” added afterwards
Prefix Hydro- Stem or root of nonmetal Suffix -icAcid HCl Hydro HI HCl is a binary acid – hydrogen + nonmetal chlorine chloric Acid iodicAcid H 2 S HydrosulfuricAcid
The obvious pattern of the name tells you that it is a binary acid. Hydro ic Acid. Therefore, you know that the acids begins with hydrogen and contains a nonmetal which you can identify between the “Hydro” and the “ic” To arrive at the formula, you “pretend” that hydrogen is +1 and using the normal charge of the nonmetal, balance the formula by adjusting their number of atoms thereby determining the subscripts.
Hydrophosphoric acid The name tells you that it is definitely a binary acid. How? The hydro prefix step 1- you find the oxidation number for phosphorus from the Periodic Table (P = -3) step 2- determine how many “H” you need at a “+1” to equal -3; answer 3 step 3- write the formula using the above ratio for the number of each element H +1 P -3 Remember that the P has a -3 charge because it is in Column 15 (group 5A) thereby signifying 5 valence electrons and a -3 charge when stable H3PH3P
Potassium acetate KC 2 H 3 O 2 Cadmium nitrate Cd(NO 3 ) 2 Aluminum oxide Al 2 O 3 Hydrosulfuric acid H 2 S Difluorine trioxide F 2 O 3 Ternary Ionic Binary Ionic Binary acid Binary molecular
These compounds begin with hydrogen since they are “acids”. Attached to the hydrogen is a polyatomic ion Hydrogen – polyatomic ion examples: H 2 SO 4 HNO 3 H 2 CO 3
Root of polyatomic ion + suffix - ic acid HClO 3 Chlor HNO 3 Nitr H 2 SO 4 Sulfur How are Ternary Acids named? There are two categories of naming depending on the suffix of the polyatomic ion. First Category First Category: If the polyatomic ion has a suffix of – ate, use the following pattern: Ternary Acid – contains the polyatomic ion chlorate (suffix= ic) becoming chloric ic Acid ic Acid ic Acid Ternary Acid – contains the polyatomic ion nitrate (suffix= ic) becoming nitric Ternary Acid – contains the polyatomic ion sulfate (suffix= ic) becoming sulfuric
Second Category: Second Category: If the polyatomic ion has a suffix of –ite, use the following pattern: Root of polyatomic ion + suffix -ousacid HNO 2 Ternary acid contains polyatomic ion, nitrite (-ite suffix) becoming nitrous. Nitrous acid HClO 2 Ternary acid contains polyatomic ion, chlorite (-ite suffix) becoming chlorous. Chlorousacid H 2 SO 3 Ternary acid contains polyatomic ion, sulfite (-ite suffix) becoming sulfurous. Sulfur ousacid
Writing Formulas for Ternary Acids First, a ternary acid is easy to distinguish from a binary acid. ALL binary acids have the prefix “hydro-”. Most Ternary acids have the prefix “hydro-” but a few do like HCN which is hydrocyanic acid- the exceptions are simply memorized. Acetic acid This is an acid, but NOT a binary acid; it’s Ternary Will begin with an “H” followed by the corresponding polyatomic ion The “-ic” suffix in the acid name tells you that the polyatomic ion must have a “-ate” suffix – acetate. To write the formula, pretend that hydrogen is +1 and balance the charges. H +1 C 2 H 3 O 2 -1 HC 2 H 3 O 2
Hypochlorous acidThis is a Ternary acid (does not begin with “hydro-”; although “hypo” it’s not the same). The “-ous” suffix indicates that the polyatomic ion in this acid has a suffix of “- ite” - hypochlorite Pretend that hydrogen is +1 and balance the charges giving you their combining ratio. H +1 ClO -1 HClO Phosphoric acid This is a Ternary acid (does not begin with “hydro-”). The “-ic” suffix indicates that the polyatomic ion in this acid has a suffix of “-ate” - phosphate H 3 PO 4 Pretend that hydrogen is +1 and balance the charges giving you their combining ratio. H +1 PO 4 -3
NOW for the Secret to SuccessPRACTICE PRACTICE PRACTICE and STILL MORE PRACTICE STILL MORE PRACTICE