Questions regarding the d-block elements, group 3-12.

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Why do complex ions not emit light from de-excitations of electrons?

I understand that complex ions are coloured due to d-orbital splitting which results in electrons being able to absorb wavelengths of visible light and become excited to the higher energy state ...
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3answers
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Why is ligand substitution only partial with copper(II) ions and ammonia?

When studying ligand substitution (at UK year 13 level), the following example has been given: \begin{align} \ce{[Cu(H2O)_6]^2+ + 2NH3 &<=> [Cu(OH)_2(H2O)_6] + 2NH4^+}\\ ...
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Oxo ligand molecular orbital diagram with metal center

With highly oxidizing metal center, we expect that the hydroxide ligand's proton becomes acidic and will be lost to the surrounding media, creating an oxo ligand. The oxo ligand is a $\pi$ basic ...
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Is hydrolytic polymerisation the mechanism by which the precipitate forms from the neutral complex?

From basic coordination chemistry and acid-base equilibria we understand that a metal hexa-aqua ion can be deprotonated until it's positive charge is balanced by the negative charge of the hydroxides ...
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Why are multiple oxidation states useful for a catalyst?

Transition elements are good catalysts because they have multiple oxidation states?Why multiple oxidation states matter?
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Why is there a difference in the colours of K₂Cr₂O₇ and K₂CrO₄?

In both the compounds the oxidation state of Chromium is +6 so why is there a difference in the colours of their aqueous solutions. $\ce{K2Cr2O7}$ is red-yellow and $\ce{K2CrO4}$ is bright yellow I ...
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Protein purification with Colbalt

Cobalt exhibits a more specific interaction with histidine tags, resulting in less nonspecific interaction than nickel. For this reason, cobalt is the preferred divalent cation for purifying ...
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1answer
115 views

Predicting orbital angular momentum effects on magnetic moments

For metal complexes with $A_{2}$ or $E$ ground state terms there is angular momentum contribution to the magnetic moment which is generally positive for more than half-filled subshells and negative ...
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Transition element

Now A transition element is one which forms one or more stable ions which have partially filled d-orbitals. Maganase (Mn) could have an oxidation state of 7+ which means that it will lose all of the ...
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What is the electronic configuration of Fe(II) ion?

The electronic configuration of Fe is 1s2 2s2 2p6 3s2 3p6 4s2 3d6. So after removing two electrons the configuration becomes: 1s2 2s2 2p6 3s2 3p6 3d6 But why cant the electrons rearrange themselves ...
2
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2answers
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Does sodium form complexes like transition metal ions?

I realise that there is a similar question here Difference between sodium ion and a transition metal ion dissolving in water? and it seems to answer my question, however I was reading about how ...
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1answer
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How can transition metals form so many bonds with ligands? [duplicate]

For instance, copper can form $\ce{[Cu(H2O)6]^2+}$ so it accepts 6 electron pairs from $\ce{H2O}$ molecules to form dative covalent bonds. However it has one electron in the 4s subshell and 10 in the ...
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Why are transition metal hydroxides insoluble?

From what I understand, adding NaOH to a solution containing transition metal ions gives transition metal hydroxide precipitates. Why is NaOH soluble but transition metal hydroxides insoluble? I have ...
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1answer
617 views

Can metals have a net negative charge

Normal metals like sodium or Calcium have a positive charge as $\ce{Na}^+$ or $\ce{Ca}^{2+}$. Transition metals have a loot of variable oxidation states. Yesterday I read about Iridium in Wikipedia ...
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How to rationalise the trend in the covalent radii of the transition metals?

Why do the covalent radii of transition series decrease at the start rapidly, then become almost constant and at the end of series begin to increase from left to right in periodic table?
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1answer
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Why is Cr²⁺ is a good reducing agent but Mn³⁺ is a good oxidising agent?

The question is the same as the title states. In my text book,the following is written $\ce{Cr^{2+}}$ gets converted to $\ce{Cr^{3+}}$ as the +3 oxidation state hase half filled $\mathrm{t_2g}$ ...
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Why is inner orbital complex more stable than outer orbital complex?

I learnt that $\ce{Cr(II)}$ ion is a stronger reducing agent than $\ce{Fe(II)}$ In an aqueous solution as inner orbital complexes more stable than outer orbital complexes? I cannot understand why is ...
5
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1answer
77 views

Why is enthalpy of atomization of Mn exceptionally low?

Transition elements usually have high values, especially so for greater number of unpaired electrons. Why the exception here?
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293 views

Why is zinc more reactive than copper?

In terms of electronegativity, from what I understand electronegativity increases going across the period, so surely this should mean that zinc less readily loses its outer shell electrons than ...
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A question about transition metal ions [closed]

Can a transition metal ion with a charge of 2+ form without valence shell s and p electrons?
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1answer
102 views

NO linear vs bent - valence electron

I'd like to count the total valence electron of following neutral complex in the ionic counting (=donor-pair): $\ce{Cl-}$ : 6e $\ce{CH3-}$: 2e $\ce{PPh3}$: 2e gives 10e from these three ligands ...
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1answer
47 views

Do Palladium(II) Chloride and Palladium (III) Chloride follow 18-Electron rule or octet rule? How to determine this?

Does $\ce{PdCl2}$ follow 18-Electron rule or octet rule? How should we determine this? http://pubchem.ncbi.nlm.nih.gov/compound/24290#section=Top ...
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1answer
133 views

Magnetic moments of tetrahedral Cobalt (II) and (III) complexes

From the spin-only formula we can predict that for tetrahedral cobalt (II) complexes $$m_{eff} = 3.87 \mu_B $$ This ignores orbital angular momentum effects, which result in higher magnetic moments ...
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1answer
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How to find the valence of transition metals

For example Fe(Z=26) Short formula: $1s^2 2s^2p^6 3s^2p^6d^6 4s^2$. If we make the electronic formula we get 4 single electrons (s=1/2), which means that the valence in normal state is 4, but in the ...
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1answer
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Is a metal hydroxide fully or partly oxidised in insufficient base?

Firstly, my question only applies to transition metal compounds with more than one hydroxide group, otherwise it would be more obvious. The reason I'm asking is in an effort to oxidise some nickel ...
2
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1answer
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Metal-Ligand-Complex and bond directions: What defines coordinate system of the complex ion? [duplicate]

I have a question concerning metal ligand complexes. In every chemistry text book I have read which treats metal ligand complexes, following situation is discussed: When 6 ligands (in octahedral ...
5
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1answer
297 views

dissociation rates: trans-effect rule in square planar complexes

In lecture we became an easy description of the trans-effect. A ligand $ \ L^t \ $ with a higher trans-effect as $ \ L \ $ ( cis to $ \ L^t \ $) leads to a faster dissociation of ligand $ \ L^d \ $ ...
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3answers
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Colour of Nickel thiocyanate

What is the colour of $\ce{C2N2NiS2}$ (Nickel thiocyanate)? In most of the web sites it only molecular weight,formula and other specifications but its colour is missing every where.
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1answer
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Is the colour of leaves due to d-d transitions in chlorophyll?

While reading a chapter on transition metals, I came to know that d-Block elements have colour compounds due to d-d transitions. A question came to my mind as to whether there is any d-d kind of ...
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relativistic effect: d-electrons in metallorganic complexes

With higher period the d-electrons of the metal are less strong bonded and therefore oxidative addition is easier for $\ce{Ir(I)}$ as for $\ce{Rh(I)}$ and much easier as for $\ce{Co(I)}$. For metal ...
2
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1answer
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Why does Co2+ have 7 electrons in the 3d orbital, and not 5 like Mn?

I'm taking general chemistry 2 this half of the summer. We are currently going over coordination complexes, ligands and transition metal ions. In particular, this question is in regards to the ligand ...
2
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1answer
108 views

What makes a ligand stronger than another?

A ligand is a neutral molecule or negative ion with at least one lone pair of electrons which forms a dative covalent bond with a complex ion that has a vacant, energetically accessible orbital. It ...
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1answer
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Explanation for increase in the number of oxidation states for transition elements from Sc to Mn of the 4th period

From Sc, to Mn, the number of oxidation states increases from one (Sc) to seven (Mn). The explanation for this is because the unpaired 3d electrons can be lost along with the 4s electrons during ...
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2answers
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Transition metal order of filling electron

There is a specific order for filling electron for transition metals, but I don't know if it applies to other elements too? Some thing to take note of in this picture is the order of 3d and 4s. My ...
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1answer
227 views

Valence Shell for Transition Metals

In transition metals, is the shell with the highest energy considered the valence shell? For example, in copper the electronic configuration is ${[Ar]\text{ } 3d^{10}\text{ } 4s^{1}}$. However, in ...
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1answer
51 views

Why is Technetium unstable?

Technetium is probably the most awkward element of the periodic table for me. It seems to me that Technetium is an exception, in the sense that it doesn't have any stable isotopes, despite having a ...
0
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1answer
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square planar geometry in metal complex

I don't understand what this statements wants to say, "Square planar geometry is favoured by ligands that can form pi bonds by accepting electrons from metal atoms or ions" How is this possible I ...
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Stability of transition metals in aqueous solution

Which is more stable in aqueous solution $\ce{Cr^{3+}}$ or $\ce{Mn^{3+}}$? And why? My approach: $\ce{Cr^{3+}}$ should be more stable as the 3d electrons will enter the $t_{2g}$ orbitals. Due to CFSE ...
3
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1answer
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Spectrochemical Series - Sigma Donor Capability

I fully understand and recognise the manner and which the series works. I cannot find any references for the change in sigma donor capability moving up the series. For example, comparing $\ce{Cl-}$ ...
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1answer
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Crystal Field Theory diagram

I need to draw a simple crystal field splitting diagram and identify the lowest-energy spin-allowed ligand field band in the electronic absorption spectrum for [MnCl6]2-. I know the basics of the ...
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1answer
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Different coloured chromium salts

Evaporating cold aqueous chromium(III) chloride produces violet crystals. However when hot aqueous chromium(III) chloride crystallizes, green crystals result. Could someone please explain the ...
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2answers
2k views

What reaction takes place when potassium iodide is added to a tetraammine copper(II) complex?

I am given a blue solid W and it contains a tetraammine copper(II) complex and a $\ce{SO_4^{2-}}$ . I added dilute sulphuric acid until the solution is pale blue; then added potassium iodide solution. ...
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what is the origin of the colour of azo dyes?

what is the origin of the colour of azo-dyes? Is it the same reason as to why transition metal complexes have colour?
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1answer
127 views

Why Gold and Silver react minimally with atmosphere?

Gold and Silver atoms interact with one another to form reasonably strong metallic bonds, but surprisingly they have almost no chemical interaction with atmosphere. How can we explain it based on the ...
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1answer
114 views

Why does $\text{Cr}^{3+}$ not have the same electron configuration as $\text{Sc}$?

To be explicit, $\text{Cr}^{3+}$ and $\text{Sc}$ have the same number of electrons, the only difference is the nuclear charge. This is not an isolated anomaly, it seems: the book I'm using claim ...
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2answers
241 views

Problems with precipitation of transition metal solution

I am trying to make a solution of "trace elements"--primarily transition metals-- for use in biological media; bacteria require elements like Cobalt, Molybdenum, iron, etc. in trace amounts. I am not ...
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1answer
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Is pyrite (FeS₂) an ionic or a covalent compound?

I have searched all over the web and found a lot of diverse explanations, but none of them are concluding exactly whether $\ce{FeS2}$ (solid - pyrite) is a covalent or an ionic compound. From ...
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Can we goldify metals?

I've read in some book that one of the old chemists was able to transform cheap metals into gold. I know that gold is an element (Au) so we can't transform a metal into Au. But as I read further it ...
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1answer
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Variable oxidation state of transition metal ions

Transition metals can form stable ions with different oxidation states. But I am confused why doesn't only the most stable state exist. Let me clarify my question more: $$\ce{Ti^{2+} -> Ti^{3+} + ...
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About Ti and Nb size [duplicate]

I am confused about the atomic size of transition elements. Why are titanium and niobium similar in size?