Chemistry: The Molecular Nature of Matter

Neil D. Jespersen, James E. Brady, Alison Hyslop

Chapter 2

Elements, Compounds, and the Periodic Table - all with Video Answers

Educators

Chapter Questions

Problem 1

In the compounds formed by $\mathrm{Li}$, $\mathrm{Na}, \mathrm{K}, \mathrm{Rb},$ and $\mathrm{Cs}$ with chlorine, how many atoms of $\mathrm{Cl}$ are there per atom of each metal? In the compounds formed by Be, $\mathrm{Mg}$, Ca, Sr, and $\mathrm{Ba}$ with chlorine, how many atoms of $\mathrm{Cl}$ are there per atom of each metal? How did this kind of information lead Mendeleev to develop his periodic table?

Ronald Prasad

Ronald Prasad

Numerade Educator

Problem 2

On what basis did Mendeleev construct his periodic table? On what basis are the elements arranged in the modern periodic table?

Ronald Prasad

Numerade Educator

Problem 3

Using their positions in the periodic table, explain why is it not surprising that strontium-90, a radioactive isotope, replaces calcium in newly formed bones.

Ronald Prasad

Numerade Educator

Problem 4

In the refining of copper, sizable amounts of silver and gold are recovered. Why is this not surprising?

Ronald Prasad

Numerade Educator

Problem 5

Why would you reasonably expect cadmium to be a contaminant in zinc but not in silver?????

Ronald Prasad

Numerade Educator

Problem 6

Using the symbol for nitrogen, ${ }_{7}^{14} \mathrm{~N}_{2}^{0},$ indicate what information is conveyed by the two superscripts, and what information is conveyed by the two subscripts.

Ronald Prasad

Numerade Educator

Problem 7

Make a rough sketch of the periodic table and mark off those areas where you would find (a) the representative elements, (b) the transition elements, and (c) the inner transition elements.

Ronald Prasad

Numerade Educator

Problem 8

Which of the following is
(a) an alkali metal? Ca, $\mathrm{Cu}$, In, $\mathrm{Li}, \mathrm{S}$
(b) a halogen? Ce, $\mathrm{Hg}, \mathrm{Si}, \mathrm{O}, \mathrm{I}$
(c) a transition element? $\mathrm{Pb}, \mathrm{W}, \mathrm{Ca}, \mathrm{Cs}, \mathrm{P}$
(d) a noble gas? $\mathrm{Xe}, \mathrm{Se}, \mathrm{H}, \mathrm{Sr}, \mathrm{Zr}$
(e) a lanthanide element? $\mathrm{Th}, \mathrm{Sm}, \mathrm{Ba}, \mathrm{F}, \mathrm{Sb}$
(f) an actinide element? Ho, $\mathrm{Mn}, \mathrm{Pu},$ At, $\mathrm{Na}$
(g) an alkaline earth metal? $\mathrm{Mg}, \mathrm{Fe}, \mathrm{K}, \mathrm{Cl}, \mathrm{Ni}$

Jennifer Hudspeth

Jennifer Hudspeth

Numerade Educator

Problem 9

Name five physical properties that we usually observe for metals.

Ronald Prasad

Numerade Educator

Problem 10

Why is mercury used in thermometers? Why is tungsten used in light bulbs?

Ronald Prasad

Numerade Educator

Problem 11

Which nonmetals occur as monatomic gases (i.e., gases whose particles consist of single atoms)?

Ronald Prasad

Numerade Educator

Problem 12

Which two elements exist as liquids at room temperature and pressure?

Ronald Prasad

Numerade Educator

Problem 13

Which physical property of metalloids distinguishes them from metals and nonmetals?

Ronald Prasad

Numerade Educator

Problem 14

Sketch the shape of the periodic table and mark off those areas where we find (a) metals, (b) nonmetals, and (c) metalloids.

Ronald Prasad

Numerade Educator

Problem 15

Most periodic tables have a heavy line that looks like a staircase starting from boron down to polonium. What information does this line convey?

Ronald Prasad

Numerade Educator

Problem 16

Which metals can you think of that are commonly used to make jewelry? Why isn't iron used to make jewelry? Why isn't potassium used?

Ronald Prasad

Numerade Educator

Problem 17

What trends-regular changes in physical or chemical properties - in the periodic table have been mentioned in this chapter?

Ronald Prasad

Numerade Educator

Problem 18

Find a periodic table on the internet that lists physical properties of the elements. Can you distinguish trends in the periodic table based on (a) melting point, (b) boiling point, or (c) density?

Ronald Prasad

Numerade Educator

Problem 19

What are two ways to interpret a chemical symbol?

Ronald Prasad

Numerade Educator

Problem 20

What is the difference between an atom and a molecule?

Aishu Sanchula

Numerade Educator

Problem 21

Write the formulas and names of the elements that exist in nature as diatomic molecules.

Ronald Prasad

Numerade Educator

Problem 22

Atoms of which elements are usually represented by the following drawings? Give their names and chemical symbols.

Ronald Prasad

Numerade Educator

Problem 23

Atoms of which elements are usually represented by the following drawings? Give their names and chemical symbols.

Ronald Prasad

Numerade Educator

Problem 24

A DNA molecule is small in actual size but contains an enormous number of atoms. Surprisingly, the molecule is made up of atoms of just five different elements. Study Figure 2.18 and identify which elements those are.

Ronald Prasad

Numerade Educator

Problem 25

What do we mean when we say a chemical equation is balanced? Why do we balance chemical equations?

Ronald Prasad

Numerade Educator

Problem 26

For a chemical reaction, what do we mean by the term reactants? What do we mean by the term products?

Ronald Prasad

Numerade Educator

Problem 27

The combustion of a thin wire of magnesium metal (Mg) in an atmosphere of pure oxygen produces the brilliant light of a flashbulb, once commonly used in photography. After the reaction, a thin film of magnesium oxide is seen on the inside of the bulb. The equation for the reaction is
$$
2 \mathrm{Mg}+\mathrm{O}_{2} \longrightarrow 2 \mathrm{MgO}
$$
(a) State in words how this equation is read.
(b) Give the formula(s) of the reactants.
(c) Give the formula(s) of the products.

Ronald Prasad

Numerade Educator

Problem 28

Describe what kind of event must occur (involving electrons) if the atoms of two different elements are to react to form an ionic compound.

Ronald Prasad

Numerade Educator

Problem 29

With what kind of elements do metals react?

Ronald Prasad

Numerade Educator

Problem 30

What is an ion? How does it differ from an atom or a molecule?

Ronald Prasad

Numerade Educator

Problem 31

Why do we use the term formula unit for ionic compounds instead of the term molecule? Can we use that term for molecules, atoms, and ions? Explain why.

Ronald Prasad

Numerade Educator

Problem 32

Consider the sodium atom and the sodium ion.
(a) Write the chemical symbol of each.
(b) Do these particles have the same number of nuclei?
(c) Do they have the same number of protons?
(d) Could they have different numbers of neutrons?
(e) Do they have the same number of electrons?

Ronald Prasad

Numerade Educator

Problem 33

Define cation, anion, and polyatomic ion.

Ronald Prasad

Numerade Educator

Problem 34

How many electrons has a titanium atom lost if it has formed the ion $\mathrm{Ti}^{4+}$ ? What are the total numbers of protons and electrons in a $\mathrm{Ti}^{4+}$ ion?

Ronald Prasad

Numerade Educator

Problem 35

If an atom gains an electron to become an ion, what kind of electrical charge does the ion have?

Ronald Prasad

Numerade Educator

Problem 36

How many electrons has a nitrogen atom gained if it has formed the ion $\mathrm{N}^{3-}$ ? How many protons and electrons are in an $\mathrm{N}^{3-}$ ion?

Ronald Prasad

Numerade Educator

Problem 37

What are the formulas of the ions formed by (a) iron, (b) cobalt, (c) mercury, (d) chromium, (e) $\mathrm{tin},$ and (f) manganese?

Ronald Prasad

Numerade Educator

Problem 38

What is wrong with the formula $\mathrm{RbCl}_{3}$ ? What is wrong with the formula $\mathrm{SNa}_{2}$ ? Rewrite the formulas so they are correct.

Ronald Prasad

Numerade Educator

Problem 39

A student wrote the formula for an ionic compound of titanium as $\mathrm{Ti}_{2} \mathrm{O}_{4}$. What is wrong with this formula? What should the formula be?

Ronald Prasad

Numerade Educator

Problem 40

Which of the following formulas are incorrect? Write the formulas for the compounds correctly. (a) $\mathrm{NaO}_{2}$, (b) $\mathrm{RbCl}$, (c) $\mathrm{K}_{2} \mathrm{~S},$ (d) $\mathrm{Al}_{2} \mathrm{Cl}_{3}$, (e) $\mathrm{MgP}_{2}$

Ronald Prasad

Numerade Educator

Problem 41

What are the formulas (including charges) for (a) cyanide ion, (b) ammonium ion, (c) nitrate ion, (d) sulfite ion, (e) chlorate ion, and (f) sulfate ion?

Ronald Prasad

Numerade Educator

Problem 42

What are the formulas (including charges) for (a) hypochlorite ion, (b) bisulfate ion, (c) phosphate ion, (d) dihydrogen phosphate ion, (e) permanganate ion, and (f) oxalate ion?

Oluwapelumi Kolawole

Oluwapelumi Kolawole

Numerade Educator

Problem 43

What are the names of the following ions?
(a) $\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-},$
(b) $\mathrm{OH}^{-}$,
(c) $\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}^{-},(\mathbf{d}) \mathrm{CO}_{3}^{2-},$
(e) $\mathrm{CN}^{-}$
(f) $\mathrm{ClO}_{4}^{-}$

Ronald Prasad

Numerade Educator

Problem 44

Write the correct formulas for the compounds formed when the following react (a) calcium and chlorine, (b) magnesium and oxygen, (c) aluminum and oxygen, and (d) sodium and sulfur.

Ronald Prasad

Numerade Educator

Problem 45

Write the unbalanced equations for the following reactions:
(a) Iron(III) hydroxide reacts with hydrogen chloride forming water and iron(III) chloride.
(b) Silver nitrate is reacted with barium chloride to form silver chloride and barium nitrate.

Ronald Prasad

Numerade Educator

Problem 46

Write the unbalanced equations for the following reactions:
(a) Propane reacts with oxygen to form carbon dioxide and water.
(b) Sodium metal is added to water and the products are sodium hydroxide and hydrogen gas.

Ronald Prasad

Numerade Educator

Problem 47

With what kind of elements do nonmetals react?

Ronald Prasad

Numerade Educator

Problem 48

Which are the only elements that exist as free, individual atoms when not chemically combined with other elements?

Ronald Prasad

Numerade Educator

Problem 49

Write chemical formulas for the elements that normally exist in nature as diatomic molecules.

Ronald Prasad

Numerade Educator

Problem 50

Which kind of elements normally combine to form molecular compounds?

Ronald Prasad

Numerade Educator

Problem 51

Why are nonmetals found in more compounds than are metals, even though there are fewer nonmetals than metals?

Ronald Prasad

Numerade Educator

Problem 52

Most compounds of aluminum are ionic, but a few are molecular. How do we know that $\mathrm{Al}_{2} \mathrm{Cl}_{6}$ is molecular?

Ronald Prasad

Numerade Educator

Problem 53

Without referring to Table 2.6 but using the periodic table, write chemical formulas for the simplest hydrogen compounds of (a) carbon, (b) nitrogen, (c) tellurium, and (d) iodine.

Ronald Prasad

Numerade Educator

Problem 54

The simplest hydrogen compound of phosphorus is phosphine, a highly flammable and poisonous compound with an odor of decaying fish. What is the formula for phosphine?

Ronald Prasad

Numerade Educator

Problem 55

Astatine, a member of the halogen family, forms a compound with hydrogen. Predict its chemical formula.

Ronald Prasad

Numerade Educator

Problem 56

Under appropriate conditions, tin can be made to form a simple molecular compound with hydrogen. Predict its formula.

Ronald Prasad

Numerade Educator

Problem 57

Write the chemical formulas for (a) methane, (b) ethane, (c) propane, and (d) butane. Give one practical use for each of these hydrocarbons.

Ronald Prasad

Numerade Educator

Problem 58

What are the formulas for (a) methanol and (b) ethanol?

Ronald Prasad

Numerade Educator

Problem 59

What is the formula for the alkane decane, which has 10 carbon atoms?

Ronald Prasad

Numerade Educator

Problem 60

Candle wax is a mixture of hydrocarbons, one of which is an alkane with 23 carbon atoms. What is the formula for this hydrocarbon?

Ronald Prasad

Numerade Educator

Problem 61

The formula for a compound is correctly given as $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}$. State two reasons why we expect this to be a molecular compound, rather than an ionic compound.

Ronald Prasad

Numerade Educator

Problem 62

Explore the internet and find a reliable source of structures for molecular compounds. For Problems 2.57 to 2.61 , print out the ball-and-stick and space-filling models of the compounds mentioned.

Lottie Adams

Numerade Educator

Problem 63

What is the difference between a binary compound and one that is diatomic? Give examples that illustrate this difference.

Ronald Prasad

Numerade Educator

Problem 64

In naming the compounds discussed in this chapter, why is it important to know whether a compound is molecular or ionic?

Ronald Prasad

Numerade Educator

Problem 65

In naming ionic compounds of the transition elements, why is it essential to give the charge on the anion?

Ronald Prasad

Numerade Educator

Problem 66

Describe (a) the three situations in which Greek prefixes are used and (b) when Roman numerals are used.

Ronald Prasad

Numerade Educator

Problem 67

The compound $\mathrm{Cr}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{3}$ is used in the tanning of leather. How many atoms of each element are given in this formula?

Ronald Prasad

Numerade Educator

Problem 68

Asbestos, a known cancer-causing agent, has a typical formula of $\mathrm{Ca}_{3} \mathrm{Mg}_{5}\left(\mathrm{Si}_{4} \mathrm{O}_{11}\right)_{2}(\mathrm{OH})_{2} .$ How many atoms of each element are given in this formula?

Ronald Prasad

Numerade Educator

Problem 69

Epsom salts is a hydrate of magnesium sulfate, $\mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O} .$ What is the formula of the substance that remains when Epsom salts is completely dehydrated?

Ronald Prasad

Numerade Educator

Problem 70

Rochelle salt is the tetrahydrate of $\mathrm{KNaC}_{4} \mathrm{H}_{4} \mathrm{O}_{6},$ which means there are four molecules of water per $\mathrm{KNaC}_{4} \mathrm{H}_{4} \mathrm{O}_{6}$ Write the formula for Rochelle salt.

Ronald Prasad

Numerade Educator

Problem 71

A molecule of acetic acid, formed when wine spoils and becomes sour, is shown below. Write the chemical formula for the molecule.

Ronald Prasad

Numerade Educator

Problem 72

A molecule of dimethyl sulfide is shown below. The compound is a sulfurous gas with a disagreeable odor produced from breakdown products of phytoplankton through biological interactions. Write the chemical formula for the molecule. Is there a way you can write this formula using parentheses?

Ronald Prasad

Numerade Educator

Problem 73

Write the chemical formula for the molecule illustrated below.

Ronald Prasad

Numerade Educator

Problem 74

Write the chemical formula for the molecule illustrated below.

Ronald Prasad

Numerade Educator

Problem 75

For the molecule in Problem $2.73,$ which of the following structural formulas is correct?

Ronald Prasad

Numerade Educator

Problem 76

For the molecule in Problem 2.74 , which of the following structural formulas is correct?

Ronald Prasad

Numerade Educator

Problem 77

How many atoms of each element are represented in each of the following formulas? For each, name the elements prescnt.
(a) $\mathrm{K}_{2} \mathrm{C}_{2} \mathrm{O}_{4}$
(b) $\mathrm{H}_{2} \mathrm{SO}_{3}$
(c) $\mathrm{C}_{12} \mathrm{H}_{26}$
(d) $\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}$,
(e) $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{HPO}_{4}$

Ronald Prasad

Numerade Educator

Problem 78

How many atoms of each kind are represented in the following formulas? For each, name the elements present.
(a) $\mathrm{H}_{3} \mathrm{PO}_{4},$
(b) $\mathrm{Ca}\left(\mathrm{H}_{2} \mathrm{PO}_{4}\right)_{2}$,
(c) $\mathrm{C}_{4} \mathrm{H}_{9} \mathrm{Br}$
(d) $\mathrm{Fe}_{3}\left(\mathrm{AsO}_{4}\right)_{2}$
(e) $\mathrm{C}_{3} \mathrm{H}_{5}(\mathrm{OH})_{3}$

Ronald Prasad

Numerade Educator

Problem 79

How many atoms of each kind are represented in the following formulas? For each, name the elements present.
(a) $\mathrm{Ni}\left(\mathrm{ClO}_{4}\right)_{2},$
(b) $\mathrm{COCl}_{2}$,
(c) $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$
(d) $\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H},$
(e) $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{HPO}_{4}$

Ronald Prasad

Numerade Educator

Problem 80

How many atoms of each kind are represented in the following formulas? For each, name the elements present.
(a) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CO}_{2} \mathrm{C}_{3} \mathrm{H}_{7}$,
(b) $\mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O}$
(c) $\mathrm{KAl}\left(\mathrm{SO}_{4}\right)_{2} \cdot 12 \mathrm{H}_{2} \mathrm{O}$
(d) $\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}$
(e) $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH}$

Ronald Prasad

Numerade Educator

Problem 81

How many atoms of each element are represented in each of the following expressions? (a) $7 \mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}$, (b) $2\left(\mathrm{NH}_{2}\right)_{2} \mathrm{CO}$ (c) $5 \mathrm{C}_{3} \mathrm{H}_{5}(\mathrm{OH})_{3}$

Ronald Prasad

Numerade Educator

Problem 82

How many atoms of each element are represented in each of the following expressions? (a) $3 \mathrm{~N}_{2} \mathrm{O},$ (b) $4\left(\mathrm{CH}_{3}\right)_{2} \mathrm{~S},$ (c) $2 \mathrm{CuSO}_{4} \cdot 5 \mathrm{H}_{2} \mathrm{O}$

Ronald Prasad

Numerade Educator

Problem 83

Consider the balanced equation
$$
2 \mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}+3 \mathrm{Na}_{2} \mathrm{CO}_{3} \longrightarrow \mathrm{Fe}_{2}\left(\mathrm{CO}_{3}\right)_{3}+6 \mathrm{NaNO}_{3}
$$
(a) How many atoms of $\mathrm{Na}$ are on each side of the equation? (b) How many atoms of $\mathrm{C}$ are on each side of the equation? (c) How many atoms of $\mathrm{O}$ are on each side of the equation? (d) How many atoms of Fe are on each side of the equation?

Ronald Prasad

Numerade Educator

Problem 84

Consider the balanced equation for the combustion of hexane, a component of gasoline:
$$
2 \mathrm{C}_{6} \mathrm{H}_{14}+19 \mathrm{O}_{2} \longrightarrow 12 \mathrm{CO}_{2}+14 \mathrm{H}_{2} \mathrm{O}
$$
(a) How many atoms of $\mathrm{C}$ are on each side of the equation?
(b) How many atoms of $\mathrm{H}$ are on each side of the equation?
(c) How many atoms of $\mathrm{O}$ are on each side of the equation?

Ronald Prasad

Numerade Educator

Problem 85

When sulfur impurities in fuels burn, they produce pollutants such as sulfur dioxide, a major contributor to acid rain. The following is a typical reaction.
On the left are reactant molecules and on the right are product molecules in a chemical reaction. Is this equation balanced? Write the formulas for the reactants and products.

Ronald Prasad

Numerade Educator

Problem 86

Race car drivers can get extra power by burning methyl alcohol with nitrous oxide. Below on the left are the reactant molecules and on the right are product molecules of the chemical reaction. Is this equation balanced? Write the formulas for the reactants and products.

Ronald Prasad

Numerade Educator

Problem 87

Is the following chemical equation for the combustion of octane $\left(\mathrm{C}_{8} \mathrm{H}_{18}\right)$, a component of gasoline, balanced?
$$
\mathrm{C}_{8} \mathrm{H}_{18}+12 \mathrm{O}_{2} \longrightarrow 8 \mathrm{CO}_{2}+9 \mathrm{H}_{2} \mathrm{O}
$$

Ronald Prasad

Numerade Educator

Problem 88

Is the following chemical equation balanced? This reaction is used for the production of nitric acid, $\mathrm{HNO}_{3}$, and is one of the reactions responsible for acid rain.

Ronald Prasad

Numerade Educator

Problem 89

Use the periodic table, but not Table $2.2,$ to write the (b) Br, (c) $\mathrm{Mg},$ (d) $\mathrm{S},$ and symbols for the ions of (a) $\mathrm{K}$ (e) Al.

Ronald Prasad

Numerade Educator

Problem 90

Use the periodic table, but not Table $2.2,$ to write the symbols for ions of (a) barium, (b) oxygen, (c) fluorine, (d) strontium, and (e) rubidium.

Ronald Prasad

Numerade Educator

Problem 91

Write formulas for ionic compounds formed between (a) $\mathrm{Na}$ and $\mathrm{Br}$, (b) $\mathrm{K}$ and $\mathrm{I},(\mathbf{c}) \mathrm{Ba}$ and $\mathrm{O},$ (d) $\mathrm{Mg}$ and $\mathrm{Br}$, (e) $\mathrm{Al}$ and $\mathrm{S},$ and $(\mathbf{f}) \mathrm{Ba}$ and $\mathrm{F}$

Ronald Prasad

Numerade Educator

Problem 92

Write formulas for ionic compounds formed between (a) $\mathrm{Al}$ and $\mathrm{Br},$ (b) $\mathrm{Rb}$ and $\mathrm{I},$ (c) $\mathrm{Sr}$ and $\mathrm{S}$, (d) $\mathrm{Mg}$ and $\mathrm{N}$, (e) Ga and $\mathrm{O},$ and $(\mathbf{f}) \mathrm{Sr}$ and $\mathrm{F}$

Ronald Prasad

Numerade Educator

Problem 93

Write the formulas for the ionic compounds formed by the following transition metals with the chloride ion, $\mathrm{Cl}^{-}$ : (a) cobalt, (b) titanium, and (c) manganese.

Ronald Prasad

Numerade Educator

Problem 94

Write the formulas for the ionic compounds formed by the following transition metals with the bromide ion, $\mathrm{Br}^{-}$ : (a) copper, (b) zinc, and (c) gold.

Ronald Prasad

Numerade Educator

Problem 95

Write formulas for the ionic compounds formed from (a) $\mathrm{K}^{+}$ and nitrate ion, (b) $\mathrm{Ca}^{2+}$ and acetate ion, (c) ammonium ion and $\mathrm{Cl}^{-},$ (d) $\mathrm{Fe}^{3+}$ and carbonate ion, and (e) $\mathrm{Mg}^{2+}$ and phosphate ion.

Ronald Prasad

Numerade Educator

Problem 96

Write formulas for the ionic compounds formed from (a) $\mathrm{Zn}^{2+}$ and hydroxide ion, (b) $\mathrm{Ag}^{+}$ and chromate ion, (c) $\mathrm{Ba}^{2+}$ and sulfite ion, (d) $\mathrm{Rb}^{+}$ and sulfate ion, and (e) $\mathrm{Li}^{+}$ and bicarbonate ion.

Ronald Prasad

Numerade Educator

Problem 97

Each of the following metals can form two compounds with oxygen. Write their formulas. (a) lead, (b) tin, (c) manganese, (d) iron, and (e) copper

Ronald Prasad

Numerade Educator

Problem 98

Write formulas for the ionic compounds formed from $\mathrm{Cl}^{-}$ and (a) cadmium ion, (b) silver ion, (c) zinc ion, and (d) nickel ion.

Ronald Prasad

Numerade Educator

Problem 99

Name the following ionic compounds: (a) CaS, (b) AlBr, (c) $\mathrm{Na}_{3} \mathrm{P}$ (d) $\mathrm{Ba}_{3} \mathrm{As}_{2}$ (e) $\mathrm{Rb}_{2} \mathrm{~S}$.

Ronald Prasad

Numerade Educator

Problem 100

Name the following ionic compounds: (a) $\mathrm{NaF},$ (b) $\mathrm{Mg}_{2} \mathrm{C}$ (c) $\mathrm{Li}_{3} \mathrm{~N}$ (d) $\mathrm{Al}_{2} \mathrm{O}_{3}$ (e) $\mathrm{K}_{2} \mathrm{Se}$

Ronald Prasad

Numerade Educator

Problem 101

Name the following molecular compounds: (a) $\mathrm{SiO}_{2}$, (b) $\mathrm{XeF}_{4}$ (c) $\mathrm{P}_{4} \mathrm{O}_{10}$ (d) $\mathrm{Cl}_{2} \mathrm{O}_{7}$

Ronald Prasad

Numerade Educator

Problem 102

Name the following molecular compounds: (a) $\mathrm{ClF}_{3}$, (b) $\mathrm{S}_{2} \mathrm{C}_{12}$ (c) $\mathrm{N}_{2} \mathrm{O}_{5},$ (d) $\mathrm{AsCl}_{5}$.

Ronald Prasad

Numerade Educator

Problem 103

Name the following ionic compounds using the Stock system:
(a) FeS,
(b) $\mathrm{CuO}$
(c) $\mathrm{SnO}_{2}$,
(d) $\mathrm{CoCl}_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O} .$

Ronald Prasad

Numerade Educator

Problem 104

Name the following ionic compounds using the Stock system:
(a) $\mathrm{Mn}_{2} \mathrm{O}_{3}$
(b) $\mathrm{Hg}_{2} \mathrm{Cl}_{2}$,
(c) $\mathrm{PbS}$,
(d) $\mathrm{CrCl}_{3} \cdot 4 \mathrm{H}_{2} \mathrm{O}$

Ronald Prasad

Numerade Educator

Problem 105

Name the following. If necessary, refer to Table 2.4 in Section 2.5. (a) $\mathrm{NaNO}_{2},$ (b) $\mathrm{KMnO}_{4},$ (c) $\mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O},$ (d) KSCN

Ronald Prasad

Numerade Educator

Problem 106

Name the following. If necessary, refer to Table 2.4 in Section 2.5. (a) $\mathrm{K}_{3} \mathrm{PO}_{4},$ (b) $\mathrm{NH}_{4} \mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2},$ (c) $\mathrm{Fe}_{2}\left(\mathrm{CO}_{3}\right)_{3},$ (d) $\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3} \cdot 5 \mathrm{H}_{2} \mathrm{O}$

Ronald Prasad

Numerade Educator

Problem 107

Identify each of the following as molecular or ionic, and give its name:
(a) $\mathrm{CrCl}_{2}$
(e) $\mathrm{KIO}_{3}$
(h) $\mathrm{AgCN}$
(b) $\mathrm{S}_{2} \mathrm{Cl}_{2}$
(f) $\mathrm{P}_{4} \mathrm{O}_{6}$
(i) $\mathrm{ZnBr}_{2}$
(c) $\mathrm{SO}_{3}$
(g) $\mathrm{CaSO}_{3}$
(j) $\mathrm{H}_{2} \mathrm{Se}$
(d) $\mathrm{NH}_{4} \mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}$

Ronald Prasad

Numerade Educator

Problem 108

Identify each of the following as molecular or ionic, and give its name:
(a) $\mathrm{V}\left(\mathrm{NO}_{3}\right)_{3}$
(e) $\mathrm{GeBr}_{4}$
(h) $\mathrm{I}_{2} \mathrm{O}_{4}$
(b) $\mathrm{Au}_{2} \mathrm{~S}$
(f) $\mathrm{K}_{2} \mathrm{CrO}_{4}$
(i) $\mathrm{I}_{4} \mathrm{O}_{9}$
(c) $\mathrm{Au}_{2} \mathrm{~S}_{3}$
(g) $\mathrm{Fe}(\mathrm{OH})_{2}$
(j) $\mathrm{P}_{4} \mathrm{Se}_{3}$
(d) $\mathrm{Co}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{2}$

Ronald Prasad

Numerade Educator

Problem 109

Write formulas for the following.
(a) sodium monohydrogen phosphate
(b) lithium selenide
(c) chromium(III) acetate
(d) disulfur decafluoride
(e) nickel(II) cyanide
(f) iron(III) oxide
(g) antimony pentafluoride

Ronald Prasad

Numerade Educator

Problem 110

Write formulas for the following.
(a) dialuminum hexachloride
(b) tetraarsenic decaoxide
(c) magnesium hydroxide
(d) copper(II) bisulfate
(e) ammonium thiocyanate
(f) potassium thiosulfate
(g) diiodine pentaoxide

Ronald Prasad

Numerade Educator

Problem 111

Write formulas for the following.
(a) ammonium sulfide
(b) chromium(III) sulfate hexahydrate
(c) silicon tetrafluoride
(d) molybdenum(IV) sulfide
(e) tin(IV) chloride
(f) hydrogen selenide
(g) tetraphosphorus heptasulfide

Ronald Prasad

Numerade Educator

Problem 112

Write formulas for the following.
(a) mercury(II) acetate
(b) barium hydrogen sulfite
(c) boron trichloride
(d) calcium phosphide
(e) magnesium dihydrogen phosphate
(f) calcium oxalate
(g) xenon tetrafluoride

Ronald Prasad

Numerade Educator

Problem 113

Which of the following formulas are incorrect? Write the correct formula if possible.
(a) $\mathrm{HgCl}$
(e) $\mathrm{MnO}_{4} \mathrm{~K}$
(b) $\mathrm{MgSO}_{3}$
(f) CaF
(c) FeS
(g) $\mathrm{NaO}_{2}$
(d) $\mathrm{AlCO}_{3}$

Ronald Prasad

Numerade Educator

Problem 114

Which of the following formulas are incorrect? Write the correct formula if possible.
(a) $\mathrm{CrO}_{4} \mathrm{Ca}$
(e) $\mathrm{CsCl}_{2}$
(b) $\mathrm{FeSO}_{3}$
(f) $\mathrm{BaBr}_{3}$
(c) $\mathrm{NH}_{4} \mathrm{H}_{2} \mathrm{PO}_{4}$
(g) $\mathrm{Ca}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$
(d) $\mathrm{TiO}_{3}$

Ronald Prasad

Numerade Educator

Problem 115

Which of the following names are incorrect? Write the correct name if possible; if there are several possibilities; write them all. If the name is correct, write the formula.
(a) iron sulfide
(b) sodium(II) chloride
(c) calcium dibromide
(d) aluminum carbonate
(e) calcium hypochlorite
(f) magnesium(III) phosphate
(g) potassium sulfide(II)

Ronald Prasad

Numerade Educator

Problem 116

Which of the following names are incorrect? Write the correct name if possible; if there are several possibilities, write them all. If the name is correct, write the formula.
(a) sulfate of barium
(b) potassium bromide
(c) iron(III) carbonate
(d) aluminum(III) phosphate
(e) calcium selenide
(f) trimagnesium diphosphate
(g) dilithium difluoride

Ronald Prasad

Numerade Educator

Problem 117

The compounds $\mathrm{Se}_{2} \mathrm{~S}_{6}$ and $\mathrm{Se}_{2} \mathrm{~S}_{4}$ have been shown to be antidandruff agents. What are their names?

Ronald Prasad

Numerade Educator

Problem 118

The compound $\mathrm{P}_{2} \mathrm{~S}_{5}$ is used to manufacture safety matches. What is the name of this compound?

Ronald Prasad

Numerade Educator

Problem 119

The following are models of molecules of two compounds composed of carbon, hydrogen, and oxygen. The one on the left is ethanol, the alcohol that's added to gasoline with the hope of reducing our dependence on foreign oil supplies. The one on the right is dimethyl ether, a compound that is a gas at room temperature and is used as an aerosol propellant. How many atoms of carbon, hydrogen, and oxygen are in each of these molecules? Find a way to write the formula of one of them using parentheses so that the two compounds can be distinguished one from the other.

Ronald Prasad

Numerade Educator

Problem 120

A student obtained a sample from an experiment that had the following composition. If the experiment was repeated and another sample was obtained, would it have to have the exact same composition? Would the results of these experiments illustrate the law of definite proportions? Explain your answer.

Ronald Prasad

Numerade Educator

Problem 121

Suppose you wanted to separate the sample illustrated in the preceding question into its constituent chemical elements. (a) Would a chemical change be sufficient? (b) If not, what could be accomplished by a chemical change? (c) Would the elements isolated by these changes necessarily be composed of individual atoms, or would at least one be composed of molecules?

Ronald Prasad

Numerade Educator

Problem 122

The elements in Group $1 \mathrm{~A}$ and Group $7 \mathrm{~A}$ of the periodic table are some of the most reactive elements. What is the difference in reactivity between these two groups?

Ronald Prasad

Numerade Educator

Problem 123

What are the formulas for mercury(I) nitrate dihydrate and mercury(II) nitrate monohydrate?

Ronald Prasad

Numerade Educator

Problem 124

Consider the following substances: $\mathrm{Cl}_{2}, \mathrm{CaO}, \mathrm{HBr}$ $\mathrm{CuCl}_{2}, \mathrm{AsH}_{3}, \mathrm{NaNO}_{3}$, and $\mathrm{NO}_{2}$
(a) Which are binary substances?
(b) Which is a triatomic molecule?
(c) In which do we find only electron sharing?
(d) Which are diatomic?
(e) In which do we find only attractions between ions?
(f) Which are molecular?
(g) Which are ionic?

Ronald Prasad

Numerade Educator

Problem 125

Write the balanced chemical equation for the reaction between elements with atomic numbers of (a) 20 and $35,$ (b) 6 and 17 (c) 13 and 16 . For each of these, determine the ratio of the mass of the heavier element to the lighter element in the compound.

Ronald Prasad

Numerade Educator

Problem 126

Write the balanced gas phase chemical equation for the reaction of dinitrogen pentoxide with sulfur dioxide to form sulfur trioxide and nitrogen oxide. What small, whole-number ratios are expected for oxygen in the nitrogen oxides and the sulfur oxides?

Ronald Prasad

Numerade Educator

Problem 127

Bromine is a diatomic molecule, and it has two isotopes, ${ }^{79} \mathrm{Br}$ and ${ }^{81} \mathrm{Br}$, with a natural abundance of about $50 \%$ for each isotope. How many different $\mathrm{Br}_{2}$ molecules can be made? What instrument would you use to distinguish between the different molecules?

Ronald Prasad

Numerade Educator

Problem 128

Write the symbols, with charges, of all atoms and ions with just ten electrons. Write all of the compounds that can be made by combining the substances with ten electrons.

Ronald Prasad

Numerade Educator

Problem 129

Using the figures below, match the image with the correct molecular formula: $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}, \mathrm{NaCl}, \mathrm{SnCl}_{4}$, and $\mathrm{H}_{2} \mathrm{O}$. Write the names of the compounds.

Ronald Prasad

Numerade Educator

Problem 130

Imagine a world where, for some reason, hydrogen and helium have not been discovered. Would Mendeleev have had enough information to predict their existence?

Ronald Prasad

Numerade Educator

Problem 131

Around 1750 Benjamin Franklin knew of two opposite types of electric charge, produced by rubbing a glass rod or amber rod with fur. He decided that the charge developed on the glass rod should be the "positive" charge, and from there on charges were defined. What would have changed if Franklin had decided the amber rod was the positive charge?

David Collins

Numerade Educator

Problem 132

Explore the internet and find a reliable source of physical properties of elements and compounds. Justify how you decided the site was reliable.

Ronald Prasad

Numerade Educator

Problem 133

Spreadsheet applications such as Microsoft Excel can display data in a variety of ways, some of which are shown throughout this book. What method of displaying periodic trends (for example, line graphs, tables, bar graphs, 3-D views, etc.) is most effective for your learning style? Explain your answer by stating why your chosen display is better than the others.

Ronald Prasad

Numerade Educator