Chapter 9 Study Guide
What is the correct name for the molecular compound NI₃ using IUPAC nomenclature rules? a) Nitrogen triiodide b) Nitrogen iodide c) Nitrogen (III) iodide d) Trinitrogen iodide
a) Nitrogen triiodide Explanation:You would name the cation first, change nothing about it. N=nitrogen. Then you would name your anion. You have three of the Iodine atoms. Place the prefix for three-tri in front of the iodine, and change the ending to -ide.
How can you determine the charges of cations of the metals in Groups 1A, 2A, and 3A? a) The charge equals the group number, and is positive. b) The charge equals 4 minus the group number, and is positive. c) The charge equals 8 minus the group number, and is positive. d) The charge equals the group number minus 8, and is negative.
a) The charge equals the group number, and is positive. Explanation: Cations found in groups 1A, 2A, and 3A have charges that are the same as their group number. A cation is a metal, and they will always have a positive charge.
Assume you know the IUPAC name of a binary molecular compound. How can you write the formula? a) Write the symbols for the two elements, and then add subscripts that correspond to the prefixes in the name. b) Write the symbols for the two elements, and then add superscripts that correspond to the prefixes in the name. c) Write the symbols. for the two elements, and then add superscripts that correspond to the charges of each atom. d) Write the symbols for the two elements, and add parentheses around them.
a) Write the symbols for the two elements, and then add subscripts that correspond to the prefixes in the name. Explanation: If you know the name of a compound, you can simply write the symbols for the cation and the anion. You would go and add subscripts to indicate how many of each atom there are.
What is the correct name for the molecular compound BCl₃ using IUPAC nomenclature rules? a) Beryllium trichloride b) Boron trichloride c) Barium chloride d) Beryllium tetrachloride
b) Boron trichloride Explanation: You are naming the molecular compound. You should name the cation, B=boron, and then the anion Cl=chlorine. You have three chlorine atoms so you should add the prefix for three, which is tri. Then you need to change the end of your anion to -ide.
What is the IUPAC name of the compound CaCO₃? a) Calcium carbonic acid b) Calcium carbonate c) Calcium hydroxide d) Calcium acetate
b) Calcium carbonate Explanation: Identify your cation, Ca=calcium. Identify your anion, CO₃=polyatomic ion carbonate. You would need to locate this on your polyatomic ion sheet. Combine the cation and the anion, and make sure that your charges balance
Which of the following is an acid that contains the anion ClO₂? a) Chloric acid b) Chlorous acid c) Hydrochloric acid d) Hydrochlorous acid
b) Chlorous acid Explanation: Look up the polyatomic ion ClO₂ on your polyatomic sheet. You will find that it is the symbol for chlorite. If you recall the rules, -ite ending changes to -ous and has no prefix.
What is the chemical formula for iron (III) hydroxide? a) I(OH)₃ b) Fe(OH)₃ c) Fe₂(OH)₃ d) FeOH₃
b) Fe(OH)₃ Explanation: Iron is a transition metal so it can have different charges. The roman numeral (III) indicates that in this case Fe has a charge of +3. You will need to balance out that charge. Each OH has a -1 charge. You will need three OH ions to balance out the charge.
What can they use as the base listed in the materials list? a) H2O b) KOH c) H2CO3 d) CaCl2
b) KOH Explanation: because a base must contain the anion (OH) hydroxide.
How does the electron configuration of an ion of a Group 1A or Group 7A element compare to that of the nearest noble gas? a) A Group 1A element has one fewer electron that a noble gas; a Group 7A element has one more electron than a noble gas. b) A Group 1A element has one more electron than a noble gas; a Group 7A element has 6 more electrons than a noble gas. c) A Group 1A element has one more electron than a noble gas; a Group 7A element has one fewer electron than a noble gas. d) An element in either group has the same electron configuration as a noble gas.
c) A Group 1A element has one more electron than a noble gas; a Group 7A element has one fewer electron than a noble gas. Explanation: If you remember a group 1A element has a 1⁺ charge because it gave up an electron so that it can "act" like a noble gas. A group 7A element has a 1⁻ charge because it took one electron so that it can "act" like a noble gas. If you think back to what they looked like before they gave up, or gained, an electron you will realize that 1A elements have one more electron than a noble gas, 7A elements have one fewer electrons than a noble gas.
Which is an accurate step in the procedure to name a binary molecular compound using IUPAC nomenclature rules? a) Write the names of the elements in any order. b) Use the prefix -mono for an element that has only one atom in the molecule. c) End the name for the second element with the suffix -ide. d) All of the above are accurate steps.
c) End the name for the second element with the suffix -ide. Explanation: First you would name your cation, then you would name your anion. Change nothing about your cation, change the ending of your anion to -ide.
What is the chemical formula for sulfurous acid? a) H₂S b) HSO₃ c) H₂SO₃ d) H₂SO₄
c) H₂SO₃ Explanation: You know that the ending -ous on your anion will change to -ite according to our rules. You need to go find sulfite on your polyatomic ion sheet, and find the symbol for sulfite, SO⁻²₃. Because it is an acid, you know that you will need to add a H. The charge on one sulfite ion is -2. The charge on one hydrogen is +1. You will need two hydrogen atoms to balance the charge.
What is the name of Rb₂S? a) Dirubidium sulfur b) Dirubidium monosulfide c) Rubidium Sulfide d) Rubidium (II) Sulfate
c) Rubidium sulfide Explanation: Name the cation (Rb=rubidium) then name the anion (S=sulur).You do not change anything about the cation, you change the ending on the anion to -ide.
What is the IUPAC name of the base Al(OH)₃? a) Aluminum (I) hydroxide b) Aluminum (II) hydroxide c) Aluminum (III) hydroxide d) Aluminum hydroxide
d) Aluminum hydroxide Explanation: Aluminum is in group 3A so the charge is +3, it has a set charge no need for roman numerals. Then add the name for OH, hydroxide.
What is the chemical formula (including charge) for the nitrate ion? a) NO₃³⁻ b) NO₄⁻ c) NO₂⁻ d) NO₃⁻
d) NO₃⁻ Explanation: You will need to find the chemical formula for nitrate on your polyatomic ion sheet. If you look, you will find that the chemical formula is NO₃⁻.
What is the chemical formula for the molecular compound diphosphorus trioxide? a) PO₃ b) 3P₂O c) P₃O₂ d) P₂O₃
d) P₂O₃ Explanation: You know that the prefix di means two, so you have P₂. You know that the prefix tri means 3, so you have O₃
What is the name of the compound with the chemical formula of SrI₂? a) Sulfur iriduim b) Sulfur diiridium c) Strontium diiodide d) Strontium iodide
d) Strontium iodide Explanation: you name the cation (Sr=strontium) then name the anion (I=iodine). You do not change anything about the cation, you change the ending on the anion to -ide.
What is the correct name for the molecular compound N₂H₄ using IUPAC nomenclature rules? a) Nitrogen tetrahydride b) Nitrogen pentahydride c) Dinitrogen tetrahydride d) Tetranitrogen dighydride
c) Dinitrogen tetrahydride Explanation: You first need to identify your cation, in this case nitrogen. You have two of the nitrogen atoms, so you need to add the prefix for two, di. Then identify your anion, hydrogen. You have four of them, so you need to add the prefix for four, tetra. You also need to change the ending of your anion to -ide.
What are the similarities and differences between polyatomic ions and monatomic ions? a) Both carry an electric charge, but polyatomic ions are made of more than one atom. b) Both act as units, but polyatomic ions carry an electric charge and monatomic ions do not. c) Both carry an electric charge, but the charge is 1+ or 1- in monatomic ions. d) Both carry an electric charge, but the charge is very slight in monatomic ions.
a) Both carry an electric charge, but polyatomic ions are made of more than one atom. Explanation: poly-means many, mono-means one. The only difference between these two types of ions is the amount of atoms making them. They will both carry electrical charges.
How do you name a binary ionic compound? a) First name the cation, and then name the anion. b) First name the anion, and then name the cation. c) Name the two elements that make up the compound in either order. d) First name the cation, and then name the nonmetal element in the compound with the suffix -ate.
a) First name the cation, and then name the anion. Explanation: A binary ionic compound consists of naming the cation, then the anion.
How do you name a compound containing a polyatomic ion? a) First name the cation, and then name the anion. b) First name the anion, and then name the cation. c) Name all of the elements that make up the compound, in order of increasing electronegativity. d) Name all of the elements that make up the compound, in order of decreasing electronegativity.
a) First name the cation, and then name the anion. Explanation: You will follow the same steps for naming any compound. First name your cation, and then name your anion. The only difference in this type of compound is that you have an anion that consists of more than one atom.
What is the chemical formula for sodium iodide? a) NaI b) INa c) Na₂I d) None of the above
a) NaI Explanation: Find your cation, which is Na. Find your anion, which is I. Make sure your charges are balanced. The charge for Na is +1, the charge for I is -1. Your charges are balanced.
What is the chemical formula for chromium (III) nitrite? a) CrN b) CrNO₃ c) Cr(NO₂)₃ d) Cr₃(NO)₃
c) Cr(NO₂)₃ Explanation: Find chromium on your periodic table (Cr is number 24). Next recognize that your anion is a polyatomic ion, nitrite and go find it on your polyatomic ion sheet. You will realize that the symbol for nitrite is (NO₂)⁻. The roman numeral indicated that the charge on your Cr ion is +3. You now know that you will need a charge of -3 to form a neutral compound. If each NO₂ has a charge of -1, you will need three of them to balance the charge. You would indicate this by placing NO₂ in parentheses and adding the subscript 3.
What is the IUPAC name of the acid HBR? a) Bromic acid b) Bromous acid c) Hydrobromic acid d) Hydrogen bromine acid
c) Hydrobromic acid Explanation: This acid doesn't contain a polyatomic ion so you know that it follows rule #1. You will need to add the prefix hydro and change the ending of the anion to -ic, then add the word acid.
What is the IUPAC name of the acid H₂S? a) Sulfuric acid b) Sulfurous acid c) Hydrosulfuric acid d) Sulfur hydride
c) Hydrosulfuric acid Explanation: This acid doesn't contain a polyatomic ion so you know that it follows rule #1. You will need to add the prefix hydro and change the ending of the anion to -ic, then add the word acid.
What is the chemical formula (including charge) for the ammonium ion? a) NH₃³⁻ b) NH₄⁻ c) NH⁴⁺ d) NH₃
c) NH⁴⁺ Explanation: You will need to find ammonium on your polyatomic ion sheet. You locate it and recognize that the chemical formula for ammonium is NH⁺₄.
Which of these chemical formulas is incorrect, and why? a) MgSO₄, because the net charge is not zero. b) BeCl₂, because the net charge is zero. c) NaF, because a metal and nonmetal cannot form a binary ionic compound. d) AsRb₃, because the anion symbol should be second.
d) AsRb₃, because the anion symbol should be second. Explanation: a) This is a correct formula because the charge of Mg is +2, the charge of the polyatomic ion SO₄ is -2, so the net charge of the compound is zero. b) This is a correct formula because the charge of Be is +2 the charge of each Cl is -1, and you have two of them. The charge of Be +2, is equal to the -2 charge of the Cl. c) This is correct because Na+1 and F-1 is a balanced ionic compound. d) As is an anion, Rb is a cation. You should always place them in order, cation and then anion.
What is the chemical formula for beryllium chloride? a) BeCl b) Be₂Cl c) 2BeCl d) BeCl₂
d) BeCl₂ Explanation: Look up the cation element beryllium on your periodic table. You will find that the symbol is Be 2+. Look up the anion chlorine on your periodic table. You will find that the symbol is Cl -1. You combine the cation and anion, and then make sure your charges are balanced. BeCl₂. You need the subscript 2 on chlorine because you need to balance out the 2+ charge.
Which of the groups contain several elements that form two or more cations of different charges? a) Groups 1A and 2A b) Groups 5A and 6A c) Groups 7A and 8A d) Groups 1B-8B
d) Groups 1B-8B Explanation: The only elements that can have more than one possible charge are the transition metals. These are located on your periodic table in Groups 1B-8B. All of the other answer choices have set charges.
What symbols generally appear in the chemical formulas of an acid and a base? a) H appears in the formula for an acid; N appears in the formula for a base. b) O appears in the formula for an acid; H appears in the formula for a base. c) H appears in the formula for an acid; C appears in the formula for a base. d) H appears in the formula for an acid; OH appears in the formula for a base.
d) H appears in the formula for an acid; OH appears in the formula for a base. Explanation: Every acid must contain a hydrogen. Every base must contain a hydroxide.
An ionic compound contains 2 potassium cations for every 1 oxygen anion. What is the chemical formula of the compound? a) P₂O b) 2KO c) K₂O₁ d) K₂O
d) K₂O Explanation: The symbol for potassium is K, and you were told that you have two of them (K₂). The symbol for oxygen is O, and you were told you have one of them (O). Your chemical formula is the cation and then the anion (K₂O).
What is the correct name of the molecular compound NCl₃ using IUPAC nomenclature rules? a) Nitrogen trichlorine b) Nitrogen chloride c) Nitrogen (III) chloride d) Nitrogen trichloride
d) Nitrogen trichloride Explanation: Start by naming your cation, in this case N which is nitrogen. Then find your anion, Cl which is chlorine. Because you are naming the molecular compound you need to place a prefix to indicate how many chloride atoms you have. Cl₃=trichloride. Nitrogen trichloride.
Which of the following lists the correct symbol for the ion that oxygen forms, the correct classification of the ion as an anion or a cation, and the name of the ion? a) O³⁻; anion, oxygen ion b) O²⁺; cation; oxygen ion c) O²⁻; anion; oxygen ion d) O²⁻; anion; oxide ion
d) O²⁻; anion; oxide ion Explanation: Oxygen is found in group 6, so you take the group number minus 8 to get the charge of oxygen (6-8=-2). You know that it is an anion with a charge of -2. This rules a and b. Next you need to remember the rule that states you must change the ending of the anion to -ide.
Which of the following best describes how the law of definite proportions is consistent with Dalton's postulates? a) Since atoms of elements combine to form compounds, a compound may be identified from the list of elements that make it up. b) Since atoms of element combine in fixed ratios to form a given compound, a compound may be identified from the ratio of its elements. c) Since atoms of elements combine in any ratio to form a given compound, the ratio of their masses in the compound may vary. d) Since atoms of elements combine in fixed ratios to form a given compound, the ratio of their masses in the compound is also fixed.
d) Since atoms of elements combine in fixed ratios to form a given compound, the ratio of their masses in the compound is also fixed. Explanation: This is the definition of the law of definite proportions. You should have looked it up when you were working on your vocabulary words.
How are names determined for bases? a) The name of the cation is followed by the name of the anion. b) The name of the anion is followed by the name of the cation. c) Add the suffix -ic to the name of the anion, followed by the word base. d) Add the suffix -ous to the name of the anion, followed by the word base.
a) The name of the cation is followed by the name of the anion. Explanation: The name of the cation followed by the anion, which will always be (OH).
How do you write the chemical formulas of compounds with polyatomic ions? a) Write the symbol of formula for the cation, then the anion; then balance the charges. b) Write the symbol or formula for the anion; then the cation; then balance the charges. c) Write the symbols for each element of the compound in order of increasing electronegativity, adding subscripts as necessary. d) Write the symbols for each element of the compound in order of decreasing electronegativity, adding subscripts as necessary.
a) Write the symbol of formula for the cation, then the anion; then balance the charges. Explanation: A polyatomic atom simply means a group of atoms working together as a single unit. The polyatomic ion in this case will be your anion. You follow the same rules that you would to write the chemical formula. First write the cation, then write the anion, and make sure your charges are balanced.
Which of the following correctly identifies the compound with the formula HClO₃ as an acid or a base and then names the compound using IUPAC nomenclature rules? a) An acid; hydrochloric acid b) An acid; chloric acid c) An acid; chlorous acid d) A base; ammonium chlorate
b) An acid; chloric acid Explanation: You know that this is an acid because it does not contain a hydroxide ion. It has a polyatomic ion, so it will follow the -ate or -ite rule, meaning it will not have the prefix hydro-. You will need to locate ClO₃ on your polyatomic ion sheet. This is the symbol for chlorate, so it will follow the -ate rule. This means that you will change the ending from -ate to -ic and add the word acid.
Which of the following lists the correct symbol for the ion that beryllium forms, the correct classification of the ion as an anion or a cation, and the name of the ion? a) Be⁻²; anion; beryllide ion b) Be⁺²; cation; beryllium ion c) Be⁺²; cation; beryllium (I) ion d) Be⁺²; anion; beryllium ion
b) Be⁺²; cation; beryllium ion Explanation: Beryllium is in group two, so you know that it is a cation. It is group two so you know that it has a set charge of plus to, it cannot have a roman numeral.
What is the IUPAC name of the base Pb(OH)₂ a) Phosphorus hydroxide b) Lead base c) Lead (II) hydroxide d) Lead (III) hydroxide
c) Lead (II) hydroxide Explanation: Because it is a base you automatically know that your anion is OH, hydroxide. You can rule out answers a and b. You have two hydroxide anions, each with a charge of -1. You need to balance out that charge, so the charge of lead must be two. You can indicate this with a roman numeral (II).
What is the name of the compound Co(NO₃)₂? a) Cobalt dinitrate b) Cobalt (II) nitrate c) Cobalt (IV) nitrate d) Monocobalt dinitrite
b) Cobalt (II) nitrate Explanation: Locate Co on your periodic table, it is the element cobalt which is a transition metal so you know that it will have a roman numeral in the answer. Next identify your anion, (NO₃), this is a polyatomic ion so you will need to find the compound on your polyatomic ion sheet. (NO₃) is nitrate, and each nitrate ion has a charge of -1. You have two of them so you need to balance a -2 charge. The charge of your cation, cobalt, must be +2. Name your cation, roman numeral two (II) and then your anion.
What is the chemical formula for cesium sulfide? a) CaS b) Cs₂S c) 2CsS d) CsS₂
b) Cs₂S Explanation: First you need to identify your cation. Locate cesium on your periodic table and understand that it's symbol is Cs. Next identify your anion, sulfide. The symbol for sulfur is S. Now you need to balance your charges. The charge of one Cs is +1, because it is in group one. The charge of one S is -2, because it is found in group 6 (6-8=-2). You need to balance your charges. If you have -2, you will need 2 cesium atoms to balance out this charge.
Which of the following correctly names the ionic compound LiF using IUPAC nomenclature rules? a) Lithium fluorine b) Lithium fluoride c) Fluorolithium d) Fluorolithide
b) Lithium fluoride Explanation: Li on the periodic table is lithium, this is your cation. F on the periodic table is flourine, this is your anion. You don't change anything about the cation, and you need to change the ending of your anion to -ide.
Which of the following correctly names the ionic compound MnCO₃ using IUPAC nomenclature rules? a) Manganese (I) carbonate b) Manganese (II) carbonate c) Manganese (III) carbonate d) Manganese carbon trioxide
b) Manganese (II) carbonate Explanation: First you need to find Mn on your periodic table. This is manganese (25 on your periodic table). You realize that this is a transition metal, so you know that you will need to include a roman numeral in your answer. Next realize that your anion is a polyatomic ion, go find it on your polyatomic sheet. CO₃ is carbonate and has a charge of -2. You now know that you need to balance the charge of -2 with one Mn, so the charge of Mn must be +2. You would write manganese (II) carbonate.
What is the chemical formula for magnesium hydrogen carbonate? a) MgHCO₆ b) Mg(HCO₃)₂ c) Mg(HCO₂)₃ d) Mg₂HCO₃
b) Mg(HCO₃)₂ Explanation: Find your cation, which is Mg. Find your anion which is located on your polyatomic ion sheet, HCO⁻₃. You know that the charge of one HCO₃ is -1, the charge of one Mg ion is +2. You will need two of the HCO₃ ions to balance out the charges.
What is the IUPAC name of the acid HNO₂? a) Nitric acid b) Nitrous acid c) Nitroxide acid d) Nitrogen dioxide acid
b) Nitrous acid Explanation: You need to follow the rules for naming acids. It has a polyatomic ion (NO₂), so it cannot follow rule #1, meaning it will not have the prefix hydro-. Go find No₂ on your polyatomic ion sheet, you will find that it is the symbol for nirtrite. Follow the rule that goes with -ite, this changes the ending to -ous.
A hydroxide group (-OH) is a component of most ________. a) acids b) bases c) ionic compounds d) molecular compounds
b) bases Explanation: All bases must contain the anion (OH)⁻
What condition regarding charge must be met when writing a chemical formula for an ionic compound? a) The charge of the cation must be 2+ or greater. b) The net charge of the compound must be either positive or negative. c) The charges of the ions must balance. d) The charge of the anion must equal -1 times the charge of the cation.
c) The charges of the ions must balance. Explanation: The only rule we have talked about is that the charge of the cation must equal the charge of the anion, to form a neutral compound. 1+ would need a 1- to form a net charge of zero.
Which of the following lists the correct symbol for the ion that tin forms when it losses 2 electrons, the correct classification of the ion as an anion or a cation, and the name of the ion? a) Sn⁻²; anion; tin (II) ion b) Sn⁺²; anion; tin ion c) Sn⁺²; cation; tin ion d) Sn⁺²; cation; tin (II) ion
d) Sn⁺²; cation; tin (II) ion Explanation: If it is losing electrons, it is a cation. Anions steal electrons. You can automatically rule out choices a and b. Sn is an element that acts as a transition metal so you know that it will have a roman numeral. If it gave up two electrons, you know that the roman numeral is (II).
Which of the following correctly names the ionic compound SnS₂ using IUPAC nomenclature rules? a) Stannic sulfide b) Tin sulfide c) Tin (II) sulfide d) Tin (IV) sulfide
d) Tin (IV) sulfide Explanation: First find Sn, your cation, on your periodic table (Tin is number 50). Next find S, your anion, on your periodic table (sulfur is number 16). You realize that you have 2 sulfur atoms. Each sulfur atom has a charge of -2 because they are found in group 6 (6-8=-2). You have two of these so your anion has an overall charge of -4. You must now balance out that -4 charge with a +4 charge. You only have one Sn atom so you know that the charge on that atom must be +4. Add a roman numeral after the Tin to indicate the charge is +4 (IV). Change the ending of your anion to -ide as per the rules for naming chemical compounds.
