3.E: Atoms, Molecules, and Ions (Exercises)

The following questions are related to the material covered in this chapter, however they may not be presented in the same order that they were in your chapter. For additional examples also check here[link to another homework set applicable]

3.1: Atomic Theory

1. List the three statements that make up the modern atomic theory.
2. Explain how atoms are composed.
3. Define atomic number. What is the atomic number for a boron atom?
4. What is the atomic number of helium?
5. Give atomic symbols for each element.

a. sodium
b. argon
c. nitrogen
d. radon

6. Give atomic symbols for each element.

a. silver

b. gold

c. mercury

d. iodine

7. Give the name of the element.

a.Si

b. Mn

c. Fe

d. Cr

8. Give the name of the element.

a. F

b. Cl

c. Br

d. I

3.2 The Periodic Table

1. Using the periodic table, classify each of the following elements as a metal or a nonmetal, and then further classify each as a main-group (representative) element, transition metal, or inner transition metal:

1. uranium
2. bromine
3. strontium
4. neon
5. gold
6. americium
7. rhodium
8. sulfur
9. carbon
10. potassium

(a) metal, inner transition metal; (b) nonmetal, representative element; (c) metal, representative element; (d) nonmetal, representative element; (e) metal, transition metal; (f) metal, inner transition metal; (g) metal, transition metal; (h) nonmetal, representative element; (i) nonmetal, representative element; (j) metal, representative element

2. Using the periodic table, classify each of the following elements as a metal or a nonmetal, and then further classify each as a main-group (representative) element, transition metal, or inner transition metal:

1. (a) cobalt
2. (b) europium
3. (c) iodine
4. (d) indium
5. (e) lithium
6. (f) oxygen
7. (g) cadmium
8. (h) terbium
9. (i) rhenium

3. Using the periodic table, identify the lightest member of each of the following groups:

1. (a) noble gases
2. (b) alkaline earth metals
3. (c) alkali metals

(a) He; (b) Be; (c) Li; (d) O

4. Using the periodic table, identify the heaviest member of each of the following groups:

(a) alkali metals

(b) noble gases

(c) alkaline earth metals

5. Use the periodic table to give the name and symbol for each of the following elements:

1. (a) the noble gas in the same period as germanium
2. (b) the alkaline earth metal in the same period as selenium
3. (c) the halogen in the same period as lithium
4. (d) the chalcogen in the same period as cadmium

(a) krypton, Kr; (b) calcium, Ca; (c) fluorine, F; (d) tellurium, Te

3.4 and 3.5: Molecular and Ionic Compounds

1) Using the periodic table, predict whether the following chlorides are ionic or covalent: KCl, NCl₃, ICl, MgCl₂, PCl₅, and CCl₄.

2) Using the periodic table, predict whether the following chlorides are ionic or covalent: SiCl₄, PCl₃, CaCl₂, CsCl, CuCl₂, and CrCl₃.

3) For each of the following compounds, state whether it is ionic or covalent. If it is ionic, write the symbols for the ions involved:

1. (a) NF₃
2. (b) BaO,
3. (c) (NH₄)₂CO₃
4. (d) Sr(H₂PO₄)₂
5. (e) IBr
6. (f) Na₂O

(a) covalent; (b) ionic, Ba²⁺, O²⁻; (c) ionic, NH+4NH4+, CO2−3CO32−; (d) ionic, Sr²⁺, H2PO−4H2PO4−; (e) covalent; (f) ionic, Na⁺, O²⁻

4) For each of the following compounds, state whether it is ionic or covalent, and if it is ionic, write the symbols for the ions involved:

1. (a) KClO₄
2. (b) MgC₂H₃O₂
3. (c) H₂S
4. (d) Ag₂S
5. (e) N₂Cl₄
6. (f) Co(NO₃)₂

5) For each of the following pairs of ions, write the symbol for the formula of the compound they will form:

1. (a) Ca²⁺, S²⁻
2. (b) NH+4NH4+, SO2−4SO42−
3. (c) Al³⁺, Br⁻
4. (d) Na⁺, HPO2−4HPO42−
5. (e) Mg²⁺, PO3−4PO43−

(a) CaS; (b) (NH₄)₂CO₃; (c) AlBr₃; (d) Na₂HPO₄; (e) Mg₃ (PO₄)₂

6) For each of the following pairs of ions, write the symbol for the formula of the compound they will form:

1. (a) K⁺, O²⁻
2. (b) NH+4NH4+, PO3−4PO43−
3. (c) Al³⁺, O²⁻
4. (d) Na⁺, CO2−3CO32−
5. (e) Ba²⁺, PO3−4PO43−

3.6: Ions and Ionic Compounds

1. Explain how cations form.
2. Explain how anions form.
3. Give the charge each atom takes when it forms an ion. If more than one charge is possible, list both.
   1. K
   2. O
   3. Co
4. Give the charge each atom takes when it forms an ion. If more than one charge is possible, list both.
   1. Ca
   2. I
   3. Fe
5. Give the charge each atom takes when it forms an ion. If more than one charge is possible, list both.
   1. Ag
   2. Au
   3. Br
6. Give the charge each atom takes when it forms an ion. If more than one charge is possible, list both.
   1. S
   2. Na
   3. H
7. Name the ions from Exercise 3.
8. Name the ions from Exercise 4.
9. Name the ions from Exercise 5.
10. Name the ions from Exercise 6.
11. Give the formula and name for each ionic compound formed between the two listed ions.
    1. Mg²⁺ and Cl⁻
    2. Fe²⁺ and O²⁻
    3. Fe³⁺ and O²⁻
12. Give the formula and name for each ionic compound formed between the two listed ions.
    1. K⁺ and S²⁻
    2. Ag⁺ and Br⁻
    3. Sr²⁺ and N³⁻
13. Give the formula and name for each ionic compound formed between the two listed ions.
    1. Cu²⁺ and F⁻
    2. Ca²⁺ and O²⁻
    3. K⁺ and P³⁻
14. Give the formula and name for each ionic compound formed between the two listed ions.
    1. Na⁺ and N³⁻
    2. Co²⁺ and I⁻
    3. Au³⁺ and S²⁻
15. Give the formula and name for each ionic compound formed between the two listed ions.
    1. K⁺ and SO₄²⁻
    2. NH₄⁺ and S²⁻
    3. NH₄⁺ and PO₄³⁻
16. Give the formula and name for each ionic compound formed between the two listed ions.
    1. Ca²⁺ and NO₃⁻
    2. Ca²⁺ and NO₂⁻
    3. Sc³⁺ and C₂H₃O₂⁻
17. Give the formula and name for each ionic compound formed between the two listed ions.
    1. Pb⁴⁺ and SO₄²⁻
    2. Na⁺ and I₃⁻
    3. Li⁺ and Cr₂O₇²⁻
18. Give the formula and name for each ionic compound formed between the two listed ions.
    1. NH₄⁺ and N³⁻
    2. Mg²⁺ and CO₃²⁻
    3. Al³⁺ and OH⁻
19. Give the formula and name for each ionic compound formed between the two listed ions.
    1. Ag⁺ and SO₃²⁻
    2. Na⁺ and HCO₃⁻
    3. Fe³⁺ and ClO₃⁻
20. Give the formula and name for each ionic compound formed between the two listed ions.
    1. Rb⁺ and O₂²⁻
    2. Au³⁺ and HSO₄⁻
    3. Sr²⁺ and NO₂⁻
21. What is the difference between SO₃ and SO₃²⁻?
22. What is the difference between NO₂ and NO₂⁻?

Answers

1. Cations form by losing electrons.
2.  
3. 1. 1+
   2. 2−
   3. 2+, 3+
4.  
5. 1. 1+
   2. 1+, 3+
   3. 1−
6.  
7. 1. the potassium ion
   2. the oxide ion
   3. the cobalt(II) and cobalt(III) ions, respectively
8.  
9. 1. the silver ion
   2. the gold(I) and gold(III) ions, respectively
   3. the bromide ion
10.  
11. 1. magnesium chloride, MgCl₂
    2. iron(II) oxide, FeO
    3. iron(III) oxide, Fe₂O₃
12.  
13. 1. copper(II) fluoride, CuF₂
    2. calcium oxide, CaO
    3. potassium phosphide, K₃P
14.  
15. 1. potassium sulfate, K₂SO₄
    2. ammonium sulfide, (NH₄)₂S
    3. ammonium phosphate, (NH₄)₃PO₄
16.  
17. 1. lead(IV) sulfate, Pb(SO₄)₂
    2. sodium triiodide, NaI₃
    3. lithium dichromate, Li₂Cr₂O₇
18.  
19. 1. silver sulfite, Ag₂SO₃
    2. sodium hydrogen carbonate, NaHCO₃
    3. iron(III) chlorate, Fe(ClO₃)₃
20.  
21. SO₃ is sulfur trioxide, while SO₃²⁻ is the sulfite ion.
22.  

3.7: Chemical Nomenclature

1) Name the following compounds:

1. (a) CsCl
2. (b) BaO
3. (c) K₂S
4. (d) BeCl₂
5. (e) HBr
6. (f) AlF₃

(a) cesium chloride; (b) barium oxide; (c) potassium sulfide; (d) beryllium chloride; (e) hydrogen bromide; (f) aluminum fluoride

2) Name the following compounds:

1. (a) NaF
2. (b) Rb₂O
3. (c) BCl₃
4. (d) H₂Se
5. (e) P₄O₆
6. (f) ICl₃

3) Write the formulas of the following compounds:

1. (a) rubidium bromide
2. (b) magnesium selenide
3. (c) sodium oxide
4. (d) calcium chloride
5. (e) hydrogen fluoride
6. (f) gallium phosphide
7. (g) aluminum bromide
8. (h) ammonium sulfate

(a) RbBr; (b) MgSe; (c) Na₂O; (d) CaCl₂; (e) HF; (f) GaP; (g) AlBr₃; (h) (NH₄)₂SO₄

4) Write the formulas of the following compounds:

1. (a) lithium carbonate
2. (b) sodium perchlorate
3. (c) barium hydroxide
4. (d) ammonium carbonate
5. (e) sulfuric acid
6. (f) calcium acetate
7. (g) magnesium phosphate
8. (h) sodium sulfite

5) Write the formulas of the following compounds:

1. (a) chlorine dioxide
2. (b) dinitrogen tetraoxide
3. (c) potassium phosphide
4. (d) silver(I) sulfide
5. (e) aluminum nitride
6. (f) silicon dioxide

(a) ClO₂; (b) N₂O₄; (c) K₃P; (d) Ag₂S; (e) AlN; (f) SiO₂

6) Write the formulas of the following compounds:

1. (a) barium chloride
2. (b) magnesium nitride
3. (c) sulfur dioxide
4. (d) nitrogen trichloride
5. (e) dinitrogen trioxide
6. (f) tin(IV) chloride

7) Each of the following compounds contains a metal that can exhibit more than one ionic charge. Name these compounds:

1. (a) Cr₂O₃
2. (b) FeCl₂
3. (c) CrO₃
4. (d) TiCl₄
5. (e) CoO
6. (f) MoS₂

(a) chromium(III) oxide; (b) iron(II) chloride; (c) chromium(VI) oxide; (d) titanium(IV) chloride; (e) cobalt(II) oxide; (f) molybdenum(IV) sulfide

8) Each of the following compounds contains a metal that can exhibit more than one ionic charge. Name these compounds:

1. (a) NiCO₃
2. (b) MoO₃
3. (c) Co(NO₃)₂
4. (d) V₂O₅
5. (e) MnO₂
6. (f) Fe₂O₃

9) The following ionic compounds are found in common household products. Write the formulas for each compound:

1. (a) potassium phosphate
2. (b) copper(II) sulfate
3. (c) calcium chloride
4. (d) titanium dioxide
5. (e) ammonium nitrate
6. (f) sodium bisulfate (the common name for sodium hydrogen sulfate)

(a) K₃PO₄; (b) CuSO₄; (c) CaCl₂; (d) TiO₂; (e) NH₄NO₃; (f) NaHSO₄

10) The following ionic compounds are found in common household products. Name each of the compounds:

1. (a) Ca(H₂PO₄)₂
2. (b) FeSO₄
3. (c) CaCO₃
4. (d) MgO
5. (e) NaNO₂
6. (f) KI

11) What are the IUPAC names of the following compounds?

1. (a) manganese dioxide
2. (b) mercurous chloride (Hg₂Cl₂)
3. (c) ferric nitrate [Fe(NO₃)₃]
4. (d) titanium tetrachloride
5. (e) cupric bromide (CuBr₂)

(a) manganese(IV) oxide; (b) mercury(I) chloride; (c) iron(III) nitrate; (d) titanium(IV) chloride; (e) copper(II) bromide

 

3.7a: Acids

1. Give the formula for each acid.
   1. perchloric acid
   2. hydriodic acid
2. Give the formula for each acid.
   1. hydrosulfuric acid
   2. phosphorous acid
3. Name each acid.
   1. HF(aq)
   2. HNO₃(aq)
   3. H₂C₂O₄(aq)
4. Name each acid.
   1. H₂SO₄(aq)
   2. H₃PO₄(aq)
   3. HCl(aq)
5. Name an acid found in food.
6. Name some properties that acids have in common.

Answers

1. 1. HClO₄(aq)
   2. HI(aq)
2.  
3. 1. hydrofluoric acid
   2. nitric acid
   3. oxalic acid
4.  
5. oxalic acid (answers will vary)

Additional Exercises

1. Use its place on the periodic table to determine if indium, In, atomic number 49, is a metal or a nonmetal.
2. Only a few atoms of astatine, At, atomic number 85, have been detected. On the basis of its position on the periodic table, would you expect it to be a metal or a nonmetal?
3. From their positions on the periodic table, will Cu and I form a molecular compound or an ionic compound?
4. From their positions on the periodic table, will N and S form a molecular compound or an ionic compound?
5. Mercury is an unusual element in that when it takes a 1+ charge as a cation, it always exists as the diatomic ion.
   1. Propose a formula for the mercury(I) ion.
   2. What is the formula of mercury(I) chloride?
6. Propose a formula for hydrogen peroxide, a substance used as a bleaching agent. (Curiously, this compound does not behave as an acid, despite its formula. It behaves more like a classic nonmetal-nonmetal, molecular compound.)
7. The uranyl cation has the formula UO₂²⁺. Propose formulas and names for the ionic compounds between the uranyl cation and F⁻, SO₄²⁻, and PO₄³⁻.
8. The permanganate anion has the formula MnO₄⁻. Propose formulas and names for the ionic compounds between the permanganate ion and K⁺, Ca²⁺, and Fe³⁺.