The document discusses the chemistry of transition metals, focusing on palladium (Pd) and its colored compounds due to the interaction of d-electrons with ligands. It explains how light absorption and the subsequent release of energy create distinct colors in these compounds, emphasizing the relationship between energy, wavelength, and the electromagnetic spectrum. The assignment includes researching oxidation states, electron configurations, and responding to classmates, with grading criteria outlined.

1. CHEM 1011 Discussion question 2
Objective
To learn more about the chemistry of transition and inner transition metals by using the Internet.
Be able to use your knowledge and understanding of transition metal chemistry to contribute to
the discussion board.
Background
In the first and second semesters of general chemistry, there is a great deal of discussion around
the Group 1A and Group 2A metals. The discussion regarding the transition and inner transition
metals is much less. Transition metals and their compounds display a variety of colors. For
example, when a sample of copper is held in a flame it produces a green flame test. Aqueous
solutions of copper compounds are blue. Adding ammonia to copper containing solutions
produces a deeper blue color.
Assignment
Choose one of the transition or inner transition metals from the periodic table: I was given
Palladium Pd.
Using your book (Chapter 23 may be very useful) and Internet resources, discuss why your
transition metal and their compounds display a variety of color. Be sure to include in your
discussion, important oxidation states, the electron configuration and how the d-electrons are
involved.
How can you include the electromagnetic spectrum and the nature of light into your discussion?
How is energy and wavelength related? Use your knowledge of the emission and absorption of
light in your discussion.
Remember to site your sources in APA style.
Respond to at least two other students.
Contribute to an ongoing discussion by responding to comments made to your posting or to
comments made by other students to other postings.
Grading
This discussion is worth 12 points. Your posting will be graded on an eight-point scale. Your
responding to two other students’ postings and your contribution to ongoing discussion is worth
four points.
Solution

2. Palladium, atomic number 46
Electronic Configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10
The main reason for colored compounds of transition metals is due to the meta's interaction and
bonding with ligands. All transition metals involve a 5 subshell d-orbital. Upon interaction with
ligands, the d-orbital's 5 subshells are differentiated due to the instability due to electrostatic
interactions with the ligand. The more instable d-shells have higher energy state than the most
stable ones. When light interacts with these compounds, the electrons present on the lower
energy d orbitals absorb specific wavelengths from the white light and get excited. This results in
the transfer of electrons from lower to higher energy state in the d orbital. When the electron falls
back from the higher energy to the lower energy, or is de-excited, it releases a wave of frequency
corresponding to the complementary color of the absorbed color. The energy required to excite
an electron or to de-excite is proportional to the difference in the lower and higher energy states
of the split-up d-orbitals, which in continuation is proportional to the ligand. Due to this
phenomenon, transition metal compounds are colored. Palladium follows the same theoretical
stance.
Energy and frequency of a light are connected through planck's constant (h), where E = h *
(frequency). Energy between the d-orbital lower and higher state determine the frequency of
absorbed wavelength.
Palladium compounds with colors:
palladium(II) chloride – red brown solid and brown solution, palladium(II) oxide – black,
potassium palladium(II) chloride – dark yellow or brown, ammonium palladium(II) chloride –
olive green, palladium(IV) chloride complex – bright red, potassium palladium(IV) chloride -
orange, palladium(II) ammine complexes – red or yellow, palladium(IV) oxide - dark red