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

learn more… | top users | synonyms

6
votes
0answers
22 views

Why are there peaks in electronegativities in d-block elements?

Looking at the Pauling electronegativities in the Periodic Table (below, from ChemWiki): Asides from the overall trend of increasing electronegativity across and up the Periodic Table (towards ...
2
votes
2answers
79 views

Why do 3d orbitals have lesser energy than 4s orbitals in transition metals? [duplicate]

This is quoted from Jim Clark's Chemguide For reasons which are too complicated to go into at this level, once you get to scandium, the energy of the 3d orbitals becomes slightly less than that of ...
4
votes
1answer
50 views

Palladium Nanocube

What is the relative permittivity and relative permeability of a palladium nanocube? If I change the size of this $\ce{Pd}$ nanocube, will these values be changed or remain the same?
2
votes
1answer
25 views

Pb-based pigments and rhodizonate salts

In a previous question, I learned that we can detect lead with sodium / potassium rhodizonate, giving a nice purple color when reacting with pure (elemental?) lead. But in the paint, lead is ...
5
votes
0answers
41 views

Trans effect on square planar complex

We've learnt about the trans effect but I have a question regarding how this plays a role with water in the equation. trans-effect: $$\ce{H2O < NH3 < Cl2}$$ Based on this, given ...
15
votes
3answers
328 views

Why are Group 11 elements unreactive?

Group 11 metals namely $\ce{Cu, Ag, Au}$ are known for their low reactivities. They are thus rightly called coinage metals and have been historically used to make currency owing to this very property ...
2
votes
1answer
44 views

Are all complexes with a polydentate ligand examples of chelation?

I'm getting a little confused about the definition of chelation and its implications (I should probably point out I'm only an A2 Chemistry student). The IUPAC defines chelation as the following: ...
3
votes
1answer
65 views

Why are compounds of V5+ and Cr6+ colored?

As far as my knowledge goes, transition metal complex ions show a color due to a transfer of electrons between the levels of split $d$-orbitals. In the case of $\ce{V^{5+}}$ and $\ce{Cr^{6+}}$ ...
4
votes
3answers
90 views

Why is mercury liquid? [duplicate]

Why is mercury the only metal that is liquid at room temperature? Note: I am a high school student and would appreciate an answer, if possible, suited for my level of understanding. Thank you.
5
votes
0answers
40 views

How many electrons in the d orbitals of NiCl2·6H2O?

On Wikipedia, it says that $\ce{NiCl2·6H2O}$ consists of separated trans-$\ce{[NiCl2(H2O)4]}$ molecules linked more weakly to adjacent water molecules. Only four of the six water molecules in ...
1
vote
0answers
55 views

Reaction between [Cu(NH3)6]2+ and NaOH [closed]

What type of reaction occurs between $\ce{[Cu(NH_3)_6]^{2+}}$ and $\ce{NaOH}$ and what are the products. And what happens when $\ce{NH_3}$ is evaporated from the product? can someone explain please.
3
votes
1answer
46 views

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 ...
11
votes
3answers
124 views

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^+}\\ ...
7
votes
0answers
47 views

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 ...
3
votes
0answers
27 views

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 ...
5
votes
1answer
53 views

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?
9
votes
1answer
111 views

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 ...
3
votes
0answers
30 views

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 ...
8
votes
1answer
142 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 ...
2
votes
0answers
80 views

Manganese (VII) oxidation state

A transition element is one which forms one or more stable ions which have partially filled d-orbitals. Manganese (Mn) could have an oxidation state of 7+ which means that it will lose all of the ...
3
votes
2answers
118 views

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
votes
1answer
77 views

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 ...
1
vote
1answer
53 views

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 ...
4
votes
1answer
80 views

Why are transition metal hydroxides insoluble?

From what I understand, adding $\ce{NaOH}$ to a solution containing transition metal ions gives transition metal hydroxide precipitates. Why is $\ce{NaOH}$ soluble but transition metal hydroxides ...
11
votes
1answer
860 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 ...
3
votes
0answers
21 views

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?
1
vote
1answer
61 views

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 $\mathrm{t_2g}$ ...
2
votes
0answers
148 views

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
votes
1answer
128 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?
1
vote
2answers
789 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 ...
-4
votes
1answer
105 views

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?
2
votes
1answer
173 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 ...
1
vote
1answer
64 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 ...
1
vote
1answer
206 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 ...
2
votes
1answer
891 views

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 ...
1
vote
1answer
45 views

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
votes
1answer
60 views

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
votes
1answer
371 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 \ $ ...
2
votes
3answers
168 views

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.
4
votes
1answer
103 views

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 ...
11
votes
0answers
141 views

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 $\ce{Ir(I)}$ than for $\ce{Rh(I)}$ and much easier than for $\ce{Co(I)}$. For ...
4
votes
2answers
2k views

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
votes
1answer
168 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 ...
1
vote
1answer
44 views

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 ...
0
votes
2answers
83 views

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 ...
1
vote
1answer
287 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 ...
1
vote
1answer
63 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
votes
1answer
55 views

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 ...
2
votes
2answers
160 views

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
votes
1answer
169 views

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 $\ce{Cl-}$ ...