Draw the three possible diastereoisomers of the triethylenetetramine complex [Co(trend)Cl2]+. Abbreviate the flexible tetradentate trien ligand H2NCH2CH2NHCH2CH2NHCH2CH2NH2 as . Which of the isomers can exist as a pair of enantiomers?
Ch.21 - Transition Elements and Coordination Chemistry
Chapter 21, Problem 21.38
Predict the number of unpaired electrons for each of the following.
(c) Zn2+
(d) Cr3+
Verified step by step guidance1
Determine the electron configuration of the neutral atom for each element.
For Zn, the electron configuration is [Ar] 3d^{10} 4s^2.
For Cr, the electron configuration is [Ar] 3d^5 4s^1.
Remove electrons according to the charge of the ion. For Zn^{2+}, remove 2 electrons from the 4s orbital. For Cr^{3+}, remove 3 electrons starting from the 4s orbital and then from the 3d orbital.
Count the number of unpaired electrons in the resulting electron configuration for each ion.

Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Electron Configuration
Electron configuration describes the distribution of electrons in an atom's orbitals. It follows the Aufbau principle, which states that electrons fill the lowest energy orbitals first. Understanding the electron configuration of an element is crucial for predicting its chemical behavior, including the number of unpaired electrons.
Recommended video:
Guided course
Electron Configuration Example
Unpaired Electrons
Unpaired electrons are those that occupy an orbital alone, without a paired electron of opposite spin. The presence of unpaired electrons is significant because it influences an atom's magnetic properties and reactivity. Atoms with unpaired electrons tend to be more reactive and can form bonds more readily.
Recommended video:
Guided course
Electron Geometry
Transition Metals and Oxidation States
Transition metals can exhibit multiple oxidation states, which affect their electron configurations. For example, when transition metals lose electrons to form cations, the electrons are typically removed from the outermost s and d orbitals. Understanding how to determine the oxidation state of an element helps in predicting the resulting electron configuration and the number of unpaired electrons.
Recommended video:
Guided course
Transition Metals
Related Practice
Textbook Question
110
views
Textbook Question
Draw all possible diastereoisomers of [Cr(C2O4)2(H2O)2]-. Which can exist as a pair of enantiomers?
118
views
Textbook Question
Which of the following complexes can exist as diastereoisomers?
(a) [Cr(NH3)2Cl4]-
(b) [Co(NH3)5Br]2+
(c) [MnCl2Br2]2- (tetrahedral)
(d) [Pt(NH3)2Br2]2-
89
views
Textbook Question
Explain why [CoCl4]2- (blue) and [Co(H2O)6]2+ (pink) have different colors. Which complex has its absorption bands at longer wavelengths?
117
views
1
rank
Textbook Question
What is the crystal field energy level diagram for the complex [Fe(NH3)6]3+?
(a)
(b)
(c)
(d)
168
views
Textbook Question
Draw a crystal field energy-level diagram, assign the electrons to orbitals, and predict the number of unpaired electrons for each of the following.
(a) [Cu(en)3]2+
(b) [FeF6]2-
(c) [Co(en)3]3+ (low spin)
93
views
