CHM1022 Lecture Notes - Lecture 8: Ionization Energy, Effective Nuclear Charge, Oxyanion

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13 Oct 2018

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All the d-block elements are metals, they form compounds in a variety of oxidation states, form coloured compounds and exhibit magnetic properties. The result of this contraction is that the properties of the first element in the group, cr, differ from those of the 2nd and 3rd members of the group, mo and w. The first ionisation energy increase down the group is due to the combination of an increase in the effective nuclear charge with a similar metallic radius (see figure 2). However, subsequent removal of electrons from the 2nd and 3rd row transition metals becomes easier due to shielding by the innermost electrons. This leads to a much more gradual increase in the second and subsequent ionisation energies. Consequently the 2nd and 3rd row elements become more stable in higher oxidation states and are much more easily oxidised in low oxidation states (+2 and +3) than the corresponding first-row transition metals.

Related Questions

1. The most stable oxidation state for niobium and tantalum is _______, while that same oxidation state for vanadium is somewhat ________.

a. 0; acidic

b. +3; reducing

c. +5; oxidizing

2. Metal-Hydrogen bond strengths in d-block elements:

a. increases down the group

b. decreases down the group

c. increases and then decrease down the group

d. decreases and then increase down the group.

3. Why does metallic bonding peak at about Group 6 and decline thereafter?

a. because after the Group 6, valence electrons begin to populate the upper, antibonding part of the d-band.

b. because with each new electron that populates each subsequent metal in the d-block, the atom gets bulkier and harder to fit in a particular structure, thus weakening the metal bond

c. because with each new electron that populates each subsequent metal in the d-block, the repulsive forces among the electrons and the nucleus grow stronger, thus weakening the metal bond

4. Suggest which interactions might be responsible for, and thus the bond order of, the metal_metal bond in the Hg₂²⁺ ion?

5. Indicate the region of the periodic table in which metal-metal bonded halide compounds are formed, giving one example.

1)The NaCl2 ionic salt does not exist. Which of the followingstatements best explains why?

A. Because the formation of Na2+ is an unfavorable process due tothe great amount of energy required to remove the 2nd electron fromthe Na atom (the 2nd electron would have to be removed from thecore electrons of the Na atom).
B. Because the Cl- anion is too large for there to be two of themattached to one Na+ ion.
C. Because NaCl2 is actually a polyatomic ion with a -1 charge, andnot an ionic salt. In the presence of another Na+ ion, the Na2Cl2salt would form.
D. Because Cl2 has no charge and therefore would not be attractedelectrostatically to the positively charged Na2+ cation.

2)Select the false statement below.

A. The first ionization energy of an atom is smaller than thesecond ionization energy of the same atom.
B. Phosphorus has a greater first ionization energy than magnesium,and the reason for this is because P has a greater effectivenuclear charge (Zeff) than Mg.
C. The following process is an endothermic process and representsthe first ionization energy of an atom A:A(g) ? A1+(g) + e1-
D. Fluorine has a greater first ionization energy than iodine, andthe reason for this is because fluorine has a greater amount ofshielding of outer electrons by inner electrons than doesiodine.

3)The Group 5A elements N,P,As have lower (less negative) electronaffinities than most of the Group 4A or Group 6A elements becauseN,P,As have half-filled subshells.

True
False

4)A fluorine atom is smaller than a bromine atom, and a potassiumatom is larger than a lithium atom.

True
False

5)A certain main-group element exhibits the following successiveionization energies in kJ/mol:

IE1 = 100; IE2 = 1200; IE3 = 2300; IE4 = 3100; IE5 = 4200

Select the false statement about this element below.

A. This is likely a Group 1A element.
B. This element is typically found uncombined in nature (that is,it is not usually found in compounds, but rather as a freeelement).
C. If this element is given a symbol of "J", it would form an ioniccompound with sulfur as J2S.
D. If this element was in period 2 of the periodic table, it wouldbe lithium.

6)Select the false statement below.

A. Generally speaking, non-metallic elements have greater effectivenuclear charge (Zeff) than metallic elements in the sameperiod.
B. Generally speaking, as you go down a group in the periodictable, there is successively greater shielding of the outer-shellelectrons by the inner-shell electrons.
C. Generally speaking, the heavier alkali metals can be predictedto exhibit greater shielding of the outer-shell electrons by theinner-shell electrons than lighter alkali metals.
D. Generally speaking, as you go across a period in the periodictable, the effective nuclear charge (Zeff) decreases because eachsuccessive element contains more protons in the nucleus than theprevious element and the outer electrons are all in the same shellas you go across a period.

7)Place the following in order of increasing size:

O2-, F1-, Li1+

A. F1- < Li1+ < O2-
B. Li1+ < O2- < F1-
C. Li1+ < F1- < O2-
D. F1- < O2- < Li1+

8)Select the false statement below.

A. The following set of quantum numbers is allowed:
n = 4, l = 2, ml = -2, ms = +1/2
B. The n = 1 shell of any given atom can accomodate up to 2electrons.
C. The n = 4 shell of any given atom can accomodate up to 16electrons.
D. In any given atom, the l = 2 subshell can accomodate up to 5electrons that have negative spins (ms =

redgoldfish403

Question 1 of 15 (worth 2 points)
The NaCl2 ionic salt does not exist. Which of the followingstatements best explains why?

A. Because the formation of Na2+ is an unfavorable process due tothe great amount of energy required to remove the 2nd electron fromthe Na atom (the 2nd electron would have to be removed from thecore electrons of the Na atom).
B. Because Cl2 has no charge and therefore would not be attractedelectrostatically to the positively charged Na2+ cation.
C. Because NaCl2 is actually a polyatomic ion with a -1 charge, andnot an ionic salt. In the presence of another Na+ ion, the Na2Cl2salt would form.
D. Because the Cl- anion is too large for there to be two of themattached to one Na+ ion.
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 2 of 15 (worth 2 points)
Select the false statement below.

A. Fluorine has a greater first ionization energy than iodine, andthe reason for this is because fluorine has a greater amount ofshielding of outer electrons by inner electrons than doesiodine.
B. The following process is an endothermic process and representsthe first ionization energy of an atom A:
A(g) ? A1+(g) + e1-

C. Phosphorus has a greater first ionization energy than magnesium,and the reason for this is because P has a greater effectivenuclear charge (Zeff) than Mg.
D. The first ionization energy of an atom is smaller than thesecond ionization energy of the same atom.
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 3 of 15 (worth 2 points)
The following process represents the first electron affinity of anatom A:

A(g) ? A1+(g) + e1-

True
False
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 4 of 15 (worth 2 points)
Generally speaking, most nonmetal atoms are smaller than most metalatoms.

True
False
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 5 of 15 (worth 2 points)
A certain main-group element exhibits the following successiveionization energies in kJ/mol:

IE1 = 100; IE2 = 1200; IE3 = 2300; IE4 = 3100; IE5 = 4200

Select the false statement about this element below.

A. If this element is given a symbol of "J", it would form an ioniccompound with sulfur as J2S.
B. This element is typically found uncombined in nature (that is,it is not usually found in compounds, but rather as a freeelement).
C. This is likely a Group 1A element.
D. If this element was in period 2 of the periodic table, it wouldbe lithium.
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 6 of 15 (worth 2 points)
Select the false statement below.

A. Generally speaking, as you go down a group in the periodictable, there is successively greater shielding of the outer-shellelectrons by the inner-shell electrons.
B. Generally speaking, non-metallic elements have greater effectivenuclear charge (Zeff) than metallic elements in the sameperiod.
C. Generally speaking, the heavier alkali metals can be predictedto exhibit greater shielding of the outer-shell electrons by theinner-shell electrons than lighter alkali metals.
D. Generally speaking, as you go across a period in the periodictable, the effective nuclear charge (Zeff) decreases because eachsuccessive element contains more protons in the nucleus than theprevious element and the outer electrons are all in the same shellas you go across a period.
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 7 of 15 (worth 2 points)
Place the following in order of increasing size:

O2-, F1-, Li1+

A. F1- < O2- < Li1+
B. F1- < Li1+ < O2-
C. Li1+ < O2- < F1-
D. Li1+ < F1- < O2-
Review
Check to review before finishing (will be flagged in Table ofContents)
Question 8 of 15 (worth 2 points)
Select the false statement below.

A. The n = 4 shell of any given atom can accomodate up to 16electrons.
B. In any given atom, the l = 2 subshell can accomodate up to 5electrons that have negative spins (ms =

CHM1022 Lecture Notes - Lecture 8: Ionization Energy, Effective Nuclear Charge, Oxyanion

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