Ch.8 - Periodic Properties of the ElementsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Trends in Ionic Radius

Concept #1: Understanding ionic radius

Example #1: Rank each set of ions in order of increasing ionic size. 

a)  K+ , Ca2+, Ar

b)  Sr2+, Na+, I 

c)   V5+, S2-, Cl 

Additional Problems
For an isoelectronic series of ions, the ion that is the smallest is always 1. the ion with the fewest protons. 2. the least positively (or most negatively) charged ion. 3. the ion with the highest atomic number. 4. the ion with the most neutrons. 5. the ion with the most electrons.
List the following ions in order of increasing radius: Na+, O 2−, Mg 2+, F −, Al 3+. A) O 2− > Mg 2+ > F − > Na+ > Al 3+ B) Na+ < Mg 2+ < Al 3+ < O 2− < F − C) O 2− < F − < Na+ < Mg 2+ < Al 3+ D) Al 3+ < Mg 2+ < Na+ < F − < O 2− E) Na+ < Mg 2+ < Al 3+ < F − < O 2−
Which ion below has the greatest radius? A. Li+  B. Na+  C. S2- D. Cl- E. Ca2+
Which ion has the largest radius? A) Cl- B) Kr+ C) Br - D) F- E) Na+
Which ion in the isoelectronic series below has the smallest radius in a crystal? A) O2- B) N3- C) Na+ D) Al3+ E) F -
Which isoelectronic ion is the  smallest ? a) Al3+ b) Na+ c) F- d) O2-
Which ion has the largest radius? a) Cl - b) F - c) K+ d) Cu2+
Which of the ions listed below would be the smallest? (a) Cl − (b) S 2− (c) K + (d) Ca 2+ (e) They will all be the same size.
Which of the following is an isoelectronic series listed with decreasing radius? a. Se2- > Br – > Kr b. Cl – > Br – > I – c. Ca2+ > Sr 2+ > Ba2+ d. Ca2+ > K + > Ar
Rank each set of ions in order of increasing ionic size. Cr7+, Sc3+, P3–, Cl–
The ionic substance strontium oxide, SrO, forms from the direct reaction of strontium metal with molecular oxygen. The arrangement of the ions in solid SrO is analogous to that in solid NaCl and is shown here. Based on the ionic radii r(O2-) = 1.40 Å and r(Sr2+) = 1.13 Å, predict the length of the side of the cube in the figure.
Why are Se2- and Br- are about the same size?
Provide a brief explanation for each of the following.S2 - is larger than O2 - .
In the ionic compounds LiF, NaCl, KBr, and RbI, the measured cation-anion distances are 2.01 Å (Li - F), 2.82 Å (Na - Cl), 3.30 Å (K - Br), and 3.67 Å (Rb - I), respectively. Predict the cation-anion distance using the values of ionic radii given in the figure.
Consider S, Cl, and K and their most common ions.Explain any differences in the orders of the atomic and ionic sizes.
Cation and anion size. Radii, in angstroms, of atoms and their ions for five groups of representative elements.How do cations of the same charge change in radius as you move down a column in the periodic table?
Arrange the following ions in order of increasing ionic radius: Br -, Te 2-, I -a. I- < Te2- < Br-b. Te2- < Br- < I-c. Br- < I-  < Te2-d. Br- < Te2- < I-e. Te2- < I- < Br-
Rank these ions according to ionic radius from largest to smallest:Na+, Mg 2+, N 3-, O 2-, F-
Place the following ions in order from smallest to largest ionic radii: Note that < means less than. K + , Ca 2+ , S 2- , and Cl - . a. S 2- < Cl - < Ca 2+ < K + b. Ca 2+ < K + < Cl - < S 2- c. S 2- < Cl - < K + < Ca 2+ d. K + < Cl - < S 2- < Ca 2+ e. Ca 2+ < K + < S 2- < Cl -
Rank the following ions from largest to smallest ionic radius.Se2-, Y3+, Rb+, Br-, Mo6+
Rank the following ions from the smallest to the largest.a) Mg2+ < Na+ < O2- < F- < N3-b) Mg2+ <  Na+ < F- < O2-  < N3-c)  Na+ < Mg2+ <  F- < O2-  < N3-d) Na+ < Mg2+ < O2- < F- < N3-e) Na+ < Mg2+ < O2- < N3- < F-
Which ion has the smallest radius?a. Ca2+b. Cl-c. K+d. S2-
Arrange the following ions, Sc3+, Cl1-, K1+, S2- in order of increasing ionic size.a. Sc3+ < K1+ < S2- < Cl1-b. K1+ < Sc3+ < Cl1- <  S2-c. Sc3+ < K1+ Cl -1 < S2-d. K1+ < Sc3+ < S2- < Cl1-
Arrange this isoelectronic series in order of increasing radius: Se2-, As3-, Rb+, and Br-.
Give three ions that are isoelectronic with neon. Place theseions in order of increasing size.
Consider the ions Sc 3+, Cl—, K+, Ca2+, and S2—. Match these ions to the following pictures that represent the relative sizes of the ions.
For the following group, place the atoms and/or ions in order of decreasing size.b. Ni2+, Pd2+, Pt 2+
For the following group, place the atoms and/or ions in order of decreasing size.d. La3+, Eu3+, Gd3+, Yb3+ 
For the following group, place the atoms and/or ions in order of decreasing size.e. Te2—, I —, Cs+, Ba2+, La3+
Put the following atoms and ions in order of increasing ionic radius: F, S2-, Cl, and Se2-.
For the following group, place the atoms and/or ions in order of decreasing size.b. Na+, K+, Rb+, Cs+
For the following group, place the atoms and/or ions in order of decreasing size.c. Te2—, I —, Cs+, Ba2+
For the following group, place the atoms and/or ions in order of decreasing size.e. O2—, S2—, Se2—, Te2—
You may want to reference (Pages 262 - 267)Section 7.3 while completing this problem.Put the following atoms and ions in order of increasing ionic radius: Br-, Rb+, Se2-, Sr2+, and Te2-.
Rank the ions in order of  increasing size, and explain your ranking: Li +, K+, Na+.
Rank the ions in order of  increasing size, and explain your ranking: Se2-, Rb+, Br -.
Which neutral atom is isoelectronic with each of the following ions: Ga3+, Zr4+, Mn7+, I-, Pb2+?
Rank the ions in order of  increasing size, and explain your ranking: O 2-, F-, N 3-.
Rank the ions in order of  decreasing size, and explain your ranking: Se 2-, S2-, O 2-.
Rank the ions in order of  decreasing size, and explain your ranking: Te 2-, Cs+, I -.
Rank the ions in order of  decreasing size, and explain your ranking: Sr 2+, Ba2+, Cs+.
Choose the larger atom or ion from each pair.(a) K or K+(b) F or F–(c) Ca2+ or Cl–
Pick the larger species from each of the following pairs.I– or Cs+
Arrange this isoelectronic series in order of decreasing radius: F–, O2–, Mg2+, Na+.
Name the element described in the following: Period 3 element whose 2− ion is isoelectronic with Ar.
Name the element described in the following: Alkaline earth metal whose cation is isoelectronic with Kr.
Why is Br– is slightly smaller than Se2–?
Which singly charged cation you would expect to be approximately the same size as Se2– and Br–?
Write the formula and name of the compound formed from the following ionic interaction: The 2+ ion and the 1− ion are both isoelectronic with the atoms of a chemically unreactive Period 4 element.
Write the formula and name of the compound formed from the following ionic interaction: The 2+ ion and the 2− ion are both isoelectronic with the Period 3 noble gas.
Enter equations that show the following processes.The fourth ionization energy of zirconium.
Write the formula and name of the compound formed from the following ionic interaction: The 2+ ion is the smallest with a filled d sublevel; the anion forms from the smallest halogen.
You may want to reference(Pages 263 - 267) Section 7.3 while completing this problem.Which ion is smaller, Co3+ or Co4+?
In a lithium ion battery that is discharging to power a device, for every Li+ that inserts into the lithium cobalt oxide electrode, a Co4+ ion must be reduced to a Co3+ ion in order to balance the charge. Using the CRC Handbook of Chemistry and Physics or other standard reference, find the ionic radii of Li+, Co3+, and Co4+. Order these ions from largest to smallest.
Arrange the atoms and/or ions in the following groups in order of decreasing size.b. Fe2+, Ni2+, Zn2+
Arrange the atoms and/or ions in the following groups in order of decreasing size.c. Ca 2+, K+, Cl -
You may want to reference (Pages 263 - 267) Section 7.3 while completing this problem.Consider the Mg2+, Cl–, K+, and Se2– ions. The four spheres below represent these four ions, scaled according to ionic size. In terms of size, between which of the spheres would you find the Ca2+ and S2– ions?
Rubidium and bromine atoms are depicted below.Which pair best represents the relative ionic sizes?
Rank the following bonds in order of increasing ionic character:N—O, Ca—O, C—F, Br—Br, K—F.
In the ionic compounds LiF, NaCl, KBr, and RbI, the measured cation-anion distances are 2.01 Å (Li - F), 2.82 Å (Na - Cl), 3.30 Å (K - Br), and 3.67 Å (Rb - I), respectively. Calculate the difference between the experimentally measured ion–ion distances and the ones predicted from the figure.
Based on their positions in the periodic table, list the following ions in order of increasing radius: K+, Ca2+, Al3+, Si4+.
List the following ions in order of increasing radius: Li +, Mg2+, Br–, Te2–.
Arrange the following in order of increasing radius and increasing ionization energy.c. Br -, Rb+, Sr 2+
Compare both the numbers of protons and electrons present in each to rank the following ions in order of increasing radius: As3–, Br –, K+, Mg2+.
The ionic radii of the ions S2–, Cl–, and K+ are 184, 181, 138 pm respectively. Explain why these ions have different sizes even though they contain the same number of electrons.
Which element has the smallest ionic radius?a. Na+ or Mg2+b. Be2+ or O2-c. F‾ or S2-
Arrange the following isoelectronic series in order of decreasing radius: F-, N3-, O2-, Mg2+, Na+ Rank ions from largest to smallest. 
Arrange the ions below in order of increasing size. Al3+                P3-                  Mg2+
Rank these ions by their expected hydration energy.
Rank these ions according to ionic radius.Ca2+, P3-, S2-, CI- , K+ 
Rank these ions according to ionic radius: Br -, Sr2+, Rb+, Se2-, As3-
The following ions contain the same number of electrons. Rank them in order of decreasing ionic radii.Cs+, I -, La3+, Sb3-, Ba2+, Te2-
The ion with the smallest diameter is ____a. Mn2+b. Cr2+c. V2+d. Ti2+e. Sc2+