Chapter 2

What is the symbol of an ion with 16 protons, 18 neutrons, and 18 electrons? What is the symbol for an ion that has 16 protons, 16 neutrons, and 18 electrons?

Would you expect each of the following atoms to gain or lose electrons when forming ions? What ion is the most likely in each case? a. \(\mathrm{Ra}\) c. \(\underline{P}\) e. \(\mathrm{Br}\) b. In d. Te f. \(\mathrm{Rb}\)

For each of the following atomic numbers, use the periodic table to write the formula (including the charge) for the simple ion that the element is most likely to form in ionic compounds. a. 13 c. 56 e. 87 b. 34 d. \(\underline{7}\) f. 35

Name the compounds in parts a-d and write the formulas for the compounds in parts e-h. a. \(\mathrm{NaBr}\) b. \(\mathrm{Rb}_{2} \mathrm{O}\) c. \(\mathrm{CaS}\) d. \(\mathrm{AlI}_{3}\) e. strontium fluoride f. aluminum selenide g. potassium nitride h. magnesium phosphide

Name the compounds in parts a-d and write the formulas for the compounds in parts e-h. a. \(\mathrm{Hg}_{2} \mathrm{O}\) b. \(\mathrm{FeBr}_{3}\) c. \(\operatorname{CoS}\) d. \(\mathrm{TiCl}_{4}\) e. tin(II) nitride f. cobalt(III) iodide g. mercury(II) oxide h. chromium(VI) sulfide

Name each of the following compounds: a. \(\mathrm{CsF}\) b. \(\mathrm{Li}_{3} \mathrm{~N}\) c. \(\mathrm{Ag}_{2} \mathrm{~S}\) d. \(\mathrm{MnO}_{2}\) e. \(\mathrm{TiO}_{2}\) f. \(\mathrm{Sr}_{3} \mathrm{P}_{2}\)

Write the formula for each of the following compounds: a. zinc chloride d. aluminum sulfide b. \(\operatorname{tin}(\mathrm{IV})\) fluoride e. mercury(I) selenide c. calcium nitride f. silver iodide

Name each of the following compounds: a. \(\mathrm{BaSO}_{3}\) c. \(\mathrm{KMnO}_{2}\) b. \(\mathrm{NaNO}_{2}\) d. \(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\)

Write the formula for each of the following compounds: a. chromium(III) hydroxide c. lead(IV) carbonate b. magnesium cyanide d. ammonium acetate

Write the formula for each of the following compounds: a. diboron trioxide c. dinitrogen monoxide b. arsenic pentafluoride d. sulfur hexachloride

Name each of the following compounds: a. CuI f. \(\mathrm{S}_{4} \mathrm{~N}_{4}\) b. \(\mathrm{CuI}_{2}\) g. \(\mathrm{SF}_{4}\) c. CoI \(_{2}\) h. \(\mathrm{NaOCl}\) d. \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) i. \(\mathrm{BaCrO}_{4}\) e. \(\mathrm{NaHCO}_{3}\) j. \(\mathrm{NH}_{4} \mathrm{NO}_{3}\)

Name each of the following compounds. Assume the acids are dissolved in water. a. \(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\) g. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) b. \(\mathrm{NH}_{4} \mathrm{NO}_{2}\) h. \(\mathrm{Sr}_{3} \mathrm{~N}_{2}\) c. \(\mathrm{Co}_{2} \mathrm{~S}_{3}\) i. \(\mathrm{Al}_{2}\left(\mathrm{SO}_{3}\right)_{3}\) d. ICl j. \(\mathrm{SnO}_{2}\) e. \(\mathrm{Pb}_{3}\left(\mathrm{PO}_{4}\right)_{2}\) k. \(\mathrm{Na}_{2} \mathrm{Cr} \mathrm{O}_{4}\) f. \(\mathrm{KClO}_{3}\) 1\. \(\mathrm{HClO}\)

Elements in the same family often form oxyanions of the same general formula. The anions are named in a similar fashion. What are the names of the oxyanions of selenium and tellurium: \(\mathrm{SeO}_{4}{\underline{\phantom{xx}}}^{2-}, \mathrm{SeO}_{3}{\underline{\phantom{xx}}}^{2-}, \mathrm{TeO}_{4}{\underline{\phantom{xx}}}^{2-}, \mathrm{TeO}_{3}{\underline{\phantom{xx}}}^{2-} ?\)

Knowing the names of similar chlorine oxyanions and acids, deduce the names of the following: \(\mathrm{IO}^{-}, \mathrm{IO}_{2}^{-}, \mathrm{IO}_{3}^{-}, \mathrm{IO}_{4}^{-}, \mathrm{HIO}\) \(\mathrm{HIO}_{2}, \mathrm{HIO}_{3}, \mathrm{HIO}_{4}\)

Write the formula for each of the following compounds: a. sulfur difluoride b. sulfur hexafluoride c. sodium dihydrogen phosphate d. lithium nitride e. chromium(III) carbonate f. tin(II) fluoride g. ammonium acetate h. ammonium hydrogen sulfate i. cobalt(III) nitrate

Write the formula for each of the following compounds: a. chromium(VI) oxide b. disulfur dichloride c. nickel(II) fluoride d. potassium hydrogen phosphate e. aluminum nitride f. ammonia g. manganese(IV) sulfide h. sodium dichromate i. ammonium sulfite j. carbon tetraiodide

Write the formula for each of the following compounds: a. sodium oxide h. copper(I) chloride b. sodium peroxide i. gallium arsenide c. potassium cyanide j. cadmium selenide d. copper(II) nitrate \(\mathbf{k}\). zinc sulfide e. selenium tetrabromide 1\. nitrous acid f. iodous acid \(\mathrm{m}\). diphosphorus pentoxide g. lead(IV) sulfide

Write the formula for each of the following compounds: a. ammonium hydrogen phosphate b. mercury(I) sulfide c. silicon dioxide d. sodium sulfite e. aluminum hydrogen sulfate f. nitrogen trichloride g. hydrobromic acid \(\mathbf{h}\). bromous acid i. perbromic acid j. potassium hydrogen sulfide k. calcium iodide 1\. cesium perchlorate

Each of the following compounds is incorrectly named. What is wrong with each name, and what is the correct name for each compound? a. \(\mathrm{FeCl}_{3}\), iron chloride b. \(\mathrm{NO}_{2}\), nitrogen(IV) oxide c. \(\mathrm{CaO}\), calcium(II) monoxide d. \(\mathrm{Al}_{2} \mathrm{~S}_{3}\), dialuminum trisulfide

Carbon- 14 dating is a method used to determine the age of historical artifacts by examining the ratio of two isotopes of carbon (carbon- 14 and carbon-12). A living plant consumes carbon dioxide in the photosynthesis process and incorporates the carbon, including \({ }^{14} \mathrm{C}\), into its molecules. As long as a plant lives, the \({ }^{14} \mathrm{C} /{ }^{12} \mathrm{C}\) ratio in its molecules remains the same as in the atmosphere because of its continuous uptake of carbon. However, as soon as a tree is cut to make a wooden bowl or a flax plant is harvested to make linen, the \({ }^{14} \mathrm{C}^{12} \mathrm{C}\) ratio begins to decrease because of the radioactive decay of \({ }^{14} \mathrm{C}\left({ }^{12} \mathrm{C}\right.\) is stable). By comparing the current \({ }^{14} \mathrm{C} /{ }^{12} \mathrm{C}\) ratio to the presumed ratio when the artifact was made, one can estimate the age of the artifact. For carbon-14 and carbon- 12 , how many protons and neutrons are in each nucleus? Assuming neutral atoms, how many electrons are present in an atom of carbon- 14 and in an atom of carbon-12?

What are the symbols for the following nonmetal elements that are most often present in compounds studied in organic chemistry: carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur. Predict a stable isotope for each of these elements.

Four \(\mathrm{Fe}^{2+}\) ions are key components of hemoglobin, the protein that transports oxygen in the blood. Assuming that these ions are \({ }^{53} \mathrm{Fe}^{2+}\), how many protons and neutrons are present in each nucleus, and how many electrons are present in each ion?

Carbohydrates, a class of compounds containing the elements carbon, hydrogen, and oxygen, were originally thought to contain one water molecule \(\left(\mathrm{H}_{2} \mathrm{O}\right)\) for each carbon atom present. The carbohydrate glucose contains six carbon atoms. Write a general formula showing the relative numbers of each type of atom present in glucose.

Give the systematic name for the following compounds that are found in everyday life. a. \(\mathrm{H}_{2} \mathrm{~S}\) (rotten egg smell) b. \(\mathrm{SO}_{2}\) (smell of burnt matches) c. \(\mathrm{SF}_{6}\) (aerosol can propellant) d. \(\mathrm{Na}_{2} \mathrm{SO}_{3}\) (dried fruit preservative)

Chlorine has two natural isotopes: \({ }_{1}^{\mathrm{j}} \mathrm{Cl}\) and \({ }_{1}{\underline{\phantom{xx}}}^{35} \mathrm{Cl} .\) Hydrogen reacts with chlorine to form the compound \(\mathrm{HCl}\). Would a given amount of hydrogen react with different masses of the two chlorine isotopes? Does this conflict with the law of definite proportion? Why or why not?

Which of the following statements is(are) true? For the false statements, correct them. a. All particles in the nucleus of an atom are charged b. The atom is best described as a uniform sphere of matter in which electrons are embedded. c. The mass of the nucleus is only a very small fraction of the mass of the entire atom. d. The volume of the nucleus is only a very small fraction of the total volume of the atom. e. The number of neutrons in a neutral atom must equal the numher of electrons.

The isotope of an unknown element, \(X\), has a mass number of 79 . The most stable ion of the isotope has 36 electrons and forms a binary compound with sodium having a formula of \(\mathrm{Na}_{2} \mathrm{X}\). Which of the following statements is(are) true? For the false statements, correct them. a. The binary compound formed between \(\mathrm{X}\) and fluorine will be a covalent compound. b. The isotope of \(\mathrm{X}\) contains 38 protons. c. The isotope of \(X\) contains 41 neutrons. d. The identity of \(X\) is strontium, \(S r\).

For each of the following ions, indicate the total number of protons and electrons in the ion. For the positive ions in the list. predict the formula of the simplest compound formed between each positive ion and the oxide ion. For the negative ions in the list, predict the formula of the simplest compound formed between each negative ion and the aluminum ion. a. \(\mathrm{Fe}^{2+}\) e. \(\mathrm{S}^{2}\) b. \(\mathrm{Fe}^{3+}\) f. \(\mathrm{P}\) c. \(\mathrm{Ba}^{2+} \quad \mathrm{g} \cdot \mathrm{Br}^{-}\) d. \(\mathrm{Cs}^{+}\) h. \(\mathrm{N}^{3-}\)

The formulas and common names for several substances are given below. Give the systematic names for these substances. a. sugar of lead \(\mathrm{Pb}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{2}\) \(\begin{array}{ll}\text { b. blue vitrol } & \mathrm{CuSO}_{4}\end{array}\) c. quicklime \(\mathrm{CaO}\) d. Epsom salts \(\mathrm{MgSO}_{.}\) e. milk of magnesia \(\quad \mathrm{Mg}(\mathrm{OH})_{2}\) f. gypsum \(\mathrm{CaSO}_{4}\) \(\mathrm{g}\). laughing gas \(\mathrm{N}_{2} \mathrm{O}\)

Identify each of the following elements: a. a member of the same family as oxygen whose most stable ion contains 54 electrons b. a member of the alkali metal family whose most stable ion contains 36 electrons c. a noble gas with 18 protons in the nucleus d. a halogen with 85 protons and 85 electrons

An element's most stable ion forms an ionic compound with bromine, having the formula \(\mathrm{XBr}_{2}\). If the ion of element \(\mathrm{X}\) has a mass number of 230 and has 86 electrons, what is the identity of the element, and how many neutrons does it have?

A certain element has only two naturally occurring isotopes: one with 18 neutrons and the other with 20 neutrons. The element forms \(1-\) charged ions when in ionic compounds. Predict the identity of the element. What number of electrons does the \(1-\) charged ion have?

The designations IA through 8 A used for certain families of the periodic table are helpful for predicting the charges on ions in binary ionic compounds. In these compounds, the metals generally take on a positive charge equal to the family number, while the nonmetals take on a negative charge equal to the family number minus eight. Thus the compound between sodium and chlorine contains \(\mathrm{Na}^{+}\) ions and \(\mathrm{Cl}^{-}\) ions and has the formula \(\mathrm{NaCl}\). Predict the formula and the name of the binary compound formed from the following pairs of elements. a. \(\mathrm{Ca}\) and \(\mathrm{N}\) e. \(\mathrm{Ba}\) and \(\mathrm{I}\) b. \(\mathrm{K}\) and \(\mathrm{O}\) f. \(\mathrm{Al}\) and Se c. \(\mathrm{Rb}\) and \(\mathrm{F}\) g. Cs and P d. \(\mathrm{Mg}\) and \(\mathrm{S}\) h. In and \(\mathrm{Br}\)

By analogy with phosphorus compounds, name the following: \(\mathrm{Na}_{3} \mathrm{AsO}_{4}, \mathrm{H}_{3} \mathrm{AsO}_{4}, \mathrm{Mg}_{3}\left(\mathrm{SbO}_{4}\right)_{2}\)

A sample of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) contains \(2.02 \mathrm{~g}\) of hydrogen, \(32.07 \mathrm{~g}\) of sulfur, and \(64.00 \mathrm{~g}\) of oxygen. How many grams of sulfur and grams of oxygen are present in a second sample of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) containing \(7.27 \mathrm{~g}\) of hydrogen?

In a reaction, \(34.0 \mathrm{~g}\) of chromium(III) oxide reacts with \(12.1 \mathrm{~g}\) of aluminum to produce chromium and aluminum oxide. If \(23.3 \mathrm{~g}\) of chromium is produced, what mass of aluminum oxide is produced?

The elements in one of the groups in the periodic table are often called the coinage metals. Identify the elements in this group based on your own experience.

Reaction of \(2.0 \mathrm{~L}\) of hydrogen gas with \(1.0 \mathrm{~L}\) of oxygen gas yields \(2.0 \mathrm{~L}\) of water vapor. All gases are at the same temperature and pressure. Show how these data support the idea that oxygen gas is a diatomic molecule. Must we consider hydrogen to be a diatomic molecule to explain these results?

A combustion reaction involves the reaction of a substance with oxygen gas. The complete combustion of any hydrocarbon (binary compound of carbon and hydrogen) produces carbon dioxide and water as the only products. Octane is a hydrocarbon that is found in gasoline. Complete combustion of octane produces 8 liters of carbon dioxide for every 9 liters of water vapor (both measured at the same temperature and pressure). What is the ratio of carbon atoms to hydrogen atoms in a molecule of octane?

A chemistry instructor makes the following claim: "Consider that if the nucleus were the size of a grape, the electrons would be about 1 mile away on average." Is this claim reasonably accurate? Provide mathematical support.

Two elements, \(\mathrm{R}\) and \(\mathrm{Q}\), combine to form two binary compounds. In the first compound, \(14.0 \mathrm{~g}\) of \(\mathrm{R}\) combines with \(3.00 \mathrm{~g}\) of \(\mathrm{Q}\). In the second compound, \(7.00 \mathrm{~g}\) of \(\mathrm{R}\) combines with \(4.50 \mathrm{~g}\) of \(\mathrm{Q}\). Show that these data are in accord with the law of multiple proportions. If the formula of the second compound is RQ, what is the formula of the first compound?

You have two distinct gaseous compounds made from element \(\mathrm{X}\) and element \(\mathrm{Y}\). The mass percents are as follows: Compound I: \(30.43 \% \mathrm{X}, 69.57 \% \mathrm{Y}\) Compound II: \(63.64 \% \mathrm{X}, 36.36 \% \mathrm{Y}\) In their natural standard states, element \(\mathrm{X}\) and element \(\mathrm{Y}\) exist as gases. (Monatomic? Diatomic? Triatomic? That is for you to determine.) When you react "gas X" with "gas Y" to make the products, you get the following data (all at the same pressure and temperature): 1 volume "gas \(\mathrm{X}^{\prime \prime}+2\) volumes "gas \(\mathrm{Y}^{\prime \prime} \longrightarrow\) 2 volumes compound \(I\) 2 volumes "gas \(\mathrm{X}^{\prime \prime}+1\) volume "gas \(\mathrm{Y}^{\prime \prime} \longrightarrow\) 2 volumes compound II Assume the simplest possible formulas for reactants and products in the chemical equations above. Then, determine the relative atomic masses of element \(\mathrm{X}\) and element \(\mathrm{Y}\).

You take three compounds, each consisting of two elements \((\mathrm{X}, \mathrm{Y}\), and \(/ \mathrm{or} \mathrm{Z})\), and decompose them to their respective elements. To determine the relative masses of \(\mathrm{X}, \mathrm{Y}\), and \(\mathrm{Z}\), you collect and weigh the elements, obtaining the following data: $$ \begin{array}{|ll|} \hline \text { Elements in Compound } & \text { Masses of Elements } \\ \hline \text { 1. } \mathrm{X} \text { and } \mathrm{Y} & \mathrm{X}=0.4 \mathrm{~g}, \mathrm{Y}=4.2 \mathrm{~g} \\ \text { 2. Y and } \mathrm{Z} & \mathrm{Y}=1.4 \mathrm{~g}, \mathrm{Z}=1.0 \mathrm{~g} \\ \text { 3. } \mathrm{X} \text { and } \mathrm{Y} & \mathrm{X}=2.0 \mathrm{~g}, \mathrm{Y}=7.0 \mathrm{~g} \\ \hline \end{array} $$ a. What are the assumptions needed to solve this problem? b. What are the relative masses of \(\mathrm{X}, \mathrm{Y}\), and \(\mathrm{Z} ?\) c. What are the chemical formulas of the three compounds? d. If you decompose \(21 \mathrm{~g}\) of compound \(\mathrm{XY}\), how much of each element is present?

What is the systematic name of \(\mathrm{Ta}_{2} \mathrm{O}_{5}\) ? If the charge on the metal remained constant and then sulfur was substituted for oxygen, how would the formula change? What is the difference in the total number of protons between \(\mathrm{Ta}_{2} \mathrm{O}_{5}\) and its sulfur analog?

A binary ionic compound is known to contain a cation with 51 protons and 48 electrons. The anion contains one-third the number of protons as the cation. The number of electrons in the anion is equal to the number of protons plus 1 . What is the formula of this compound? What is the name of this compound?

You have gone back in time and are working with Dalton on a table of relative masses. Following are his data. \(0.602 \mathrm{~g}\) gas A reacts with \(0.295 \mathrm{~g}\) gas \(\mathrm{B}\) \(0.172 \mathrm{~g}\) gas \(\mathrm{B}\) reacts with \(0.401 \mathrm{~g}\) gas \(\mathrm{C}\) \(0.320 \mathrm{~g}\) gas \(\mathrm{A}\) reacts with \(0.374 \mathrm{~g}\) gas \(\mathrm{C}\) a. Assuming simplest formulas \((\mathrm{AB}, \mathrm{BC}\), and \(\mathrm{AC}\) ), construct a table of relative masses for Dalton. b. Knowing some history of chemistry, you tell Dalton that if he determines the volumes of the gases reacted at constant temperature and pressure, he need not assume simplest formulas. You collect the following data: 6 volumes gas \(A+1\) volume gas \(B \rightarrow 4\) volumes product 1 volume gas \(\mathrm{B}+4\) volumes gas \(\mathrm{C} \rightarrow 4\) volumes product 3 volumes gas \(\mathrm{A}+2\) volumes gas \(\mathrm{C} \rightarrow 6\) volumes product Write the simplest balanced equations, and find the actual relative masses of the elements. Explain your reasoning.