Question

Based on crystal field theory, which of the following metal ions will not be colored when placed in an octahedral crystal field?

Au+
Fe3+
Ag+
Au3+
Nb3+

Answer 1

Look up the electron configuration for the element (if you don't have that in your text you can go to www.webelemets.com and click on the element, then scroll down on the left side to electron shell properties to obtain them). I'll do the first one.

Au is [Xe]4f14 5d10 6s1; therefore, the Au^+ must have the 6s1 electron removed and it will be [Xe]4f14 5d10. None of the electrons is unpaired and when split in a field all still will be paired; therefore, no color.
The Au^3+ ion is
[Xe]4f14 5d8.
......e_g......t_2g
.....><..><..>............>..>
(Note: < is for spin of the electron up and < is for the opposite.)
There will be unpaired electrons; therefore, Au^3+ salts should be colored.

You do the others the same way.

Answer 2

Two problems. The spacing is not done very well and I interchanged the e_g and t_2g. I'll try again.

.....t_2g......e_g
.....><..><..>...................>..>

Answer 3

.....t_2g.............

.....><..><..>......<..<

Answer 4

.....t_2g.........e_g

.....><..><..>.......>..>

Answer 5

Just move the e_g heading to the right so the two unpaired electrons are under that column.

Answer 6

[AI-generated answer — Explain Bot]

To determine which metal ions will not be colored when placed in an octahedral crystal field based on crystal field theory, we need to consider the number of d electrons in each metal ion.

In an octahedral crystal field, the d orbitals split into two sets: the lower energy (eg) set and the higher energy (t2g) set. The energy difference between these sets determines the color of the complex.

According to crystal field theory:
- If the metal ion has zero, one, or two d electrons, it will not absorb visible light and will appear colorless.
- If the metal ion has three to seven d electrons, it will absorb visible light and appear colored.

Let's analyze each metal ion:
1. Au+: It has one d electron (5d^10 6s^1). Therefore, it will not be colored and appear colorless.
2. Fe3+: It has five d electrons (3d^5). Therefore, it will absorb visible light and appear colored.
3. Ag+: It has zero d electrons (4d^10 5s^1). Therefore, it will not be colored and appear colorless.
4. Au3+: It has zero d electrons (5d^10). Therefore, it will not be colored and appear colorless.
5. Nb3+: It has three d electrons (4d^3). Therefore, it will absorb visible light and appear colored.

Based on crystal field theory, Au+ and Ag+ will not be colored when placed in an octahedral crystal field, while Fe3+ and Nb3+ will be colored. Therefore, the correct answer is Au+ and Ag+.