Homework Chapter 5
Chapter 5 - 5.1
1. a) Who is credited with developing a method that led to the determination of standard relative atomic masses?
b) Who discovered the periodic law?
c) Who established atomic numbers as the basis for organizing the periodic table?
2. State the periodic law.
3. How do the atomic numbers of the elements within each of Groups 1,2, and 13-18 of the periodic table vary?
4. Describe the contributions made by the following scientists to the development of the periodic table:
a) Stanislao Cannizzaro
b) Dmitri Mendeleev
c) Henry Moseley.
Chapter 5 - 5.2
1. Without looking at the periodic table, give the groups, period, and block in which the element with the electron configuration [Kr] 5s1 is located.
2. a) Without looking at the periodic table, write the group configuration for the Group 2 elements.
b) Without looking at the periodic table, write the complete electron configuration for the Group 2 element in the fourth period.
c) Refer to Figure 5-6 in your textbook to identify the element described in b) above. Then write the element’s noble gas notation.
d) How does the reactivity of the element in b) above compare with the reactivity of the element in Group 1 of the same period?
Chapter 5 - 5.3
1. a) Without looking at the periodic table, identify the period, block, and group in which the element with the electron configuration [Ar] 4s2 3d10 is located.
b) Refer to the periodic table to identify the element described in a) above and to write the element’s noble gas notation.
Chapter 5 - 5.4
1. a) Without looking at the periodic table, write the outer electron configuration for the Group 17 element in the third period.
b) Name the element described in 1 a) above and identify it as a metal, nonmetal, or metalloid.
2. a) Without looking at the periodic table, identify the period, block and group of an element with the electron configuration [Ar] 4s2 3d10 4p3
b) Name the element described in 2 a) above and identify it as a metal, nonmetal, or metalloid.
Chapter 5 - 5.5
1. For each of the following, identify the block, period, group, group, group name (where appropriate), element name, element type (metal, nonmetal, or metalloid), and relative reactivity (high or low):
a) [He] 2s2 2p5
b) [Ar] 4s1 3d10
c) [Kr] 5s1
2. Into what four blocks can the periodic table be divided to illustrate the relationship between the elements’ electron configurations and their placement in the periodic table?
3. What name is given to each of the following groups of elements on the periodic table:
a) Group 1
b) Group 2
c) Group 3-12
d) Group 17
e) Group 18
4. What are the relationships between group configuration and group number for elements in the s, p, and d blocks?
5. Without looking at the periodic table, write the outer electron configuration for Group 15 element in the fourth period.
6. Without looking at the periodic table, identify the period, block, and group of the element with the electron configuration [Ar] 4s2 3d7
7. a) How do the electron configurations within the sam group of elements compare?
b) Why are the noble gases relatively unreactive?
8. What is the relationship between the outer shell electron configuration of an element and the period in which that element appears in the periodic table?
9. List four characteristics properties of the alkali metals.
10. What name is sometimes used to refer to the entire set of d block elements?
11. List three characteristic properties of the halogens.
12. Which are the main group elements?
Chapter 5 - 5.6
1. Of the elements Li, O, C, and F, identify the one with the largest atomic radius and the one with the smallest atomic radius.
2. Of the elements Br, At, F, I, and Cl, identify the one with the smallest atomic radius and the one with the largest atomic radius.
3. a) Define atomic radius.
b) What trend is observed among the atomic radii of main group elements across a period?
c) How can this trend be explained?
4. a) What trend is observed among the atomic radii of main group elements down a group?
b) How can this trend be explained?
Chapter 5 - 5.7
1. Consider the four hypothetical main group elements Q, R, T, and X with the outer electron configurations indicated below. Then answer the questions that follow:
Q: 3s2 3p5 R: 3s1 T: 5s2 4d10 5p5 X: 5s2 4d10 5p1
a) Identify the block location of each hypothetical main group element.
b) Which of these elements are in the sam period? Which are in the sam group?
c) Which element would you expect to have the highest first ionization energy? Which would have the lowest first ionization energy?
d) Which element would you expect to have the highest second ionization energy?
e) Which of the elements is most likely to form a 1+ ion?
2. Define each of the following:
a) ion
b) ionization
c) first ionization energy
d) second ionization energy
3. a) How do the first ionization energies of the main group elements vary across a period and down a group?
b) Explain the basis for each trend.
4. For each of the following groups, indicate whether electrons are more likely to be lost or gained in compound formation and give the number of such electrons typically involved:
a) Group 1
b) Group 2
c) Group 13
d) Group 16
e) Group 17
f) Group 18
5. Which of the following cations is least likely to form: Sr2+ , Al3+ , K2+ and explain your answer.
Chapter 5 - 5.8
1. a) Define electron affinity.
b) What signs are associated with electron affinity values, and which is the significance of each sign?
2. Without looking at the electron affinity table, arrange the following elements in order of decreasing electron affinities: C, O, Li, Na, Rb, and F.
Chapter 5 - 5.9
1. a) Distinguish between a cation and an anion.
b) ow does the size of each compare with the size of the neutral atom from which it is formed?
2. The two ions K+ and Ca2+ each have 18 electrons surrounding the nucleus. Which would you expect to have the smaller radius? Explain why.
Chapter 5 - 5.10
1. a) What are the valence electrons?
b) Where are such electrons located?
Chapter 5 - -5.11
1. Consider the five hypothetical main group elements E, G, J, L, and M with the outer electron configurations shown below:
E: 2s2 2p5 G: 5s2 4d10 5p5 J: 2s2 2p2 L: 6s2 5d10 6p5 M: 2s2 2p4
a) Identify the block location for each element. Then determine which elements are in the same period and which are in the same group.
b) Which element would you expect to have the highest electron affinity? Which would you expect to form a 1- ion? Which should have the highest electronegativity?
c) Compare the ionic radius of the typical ion formed by the element G with the radius of its neutral atom.
d) Which element(s) contain seven valence electrons?
2. Identify the most and least electronegative groups of elements in the periodic table.
3. Which element is the most electronegative among C, N, O, Br, and S? To which group does it belong?
Chapter 5 - 5.12
1. State the general period and group trends among main-group elements with respect to each of the following properties: a) atomic radii; b) first ionization energy; c) electron affinity; d) ionic radii; e) electronegativity.
2. Among the main-group elements, what is the relationship between group number and the number of valence electrons among group members?
3. a) In general, how do th eperiodic properties of the d block elements compare with those of the main-group elements?
b) Explain the comparisons made in a) above.