Advertisements
Advertisements
Question
NF3 is possible, but NF5 is not. Why?
Advertisements
Solution
According to the electronic configuration of nitrogen, it does not have 3d orbital that's why it can't expand the valency up to 5 and does not form .
N does not have vacant d orbitals. Hence, there is no excitation of ns2 electron to vacant orbitals. Thus, has only three unpaired electrons in p-orbitals showing +3 oxidation state and not +5 in halides like other elements of group.
APPEARS IN
RELATED QUESTIONS
Account for the following:
Zn is not considered as a transition element.
Account for the following:
E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+.
Which is a stronger reducing agent, Cr2+ or Fe2+ and why?
Compare the stability of +2 oxidation state for the elements of the first transition series.
How would you account for the following:
Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.
Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.
What can be inferred from the magnetic moment value of the following complex species?
| Example | Magnetic Moment (BM) |
| K2[MnCl4] | 5.9 |
Following are the transition metal ions of 3d series:
Ti4+, V2+, Mn3+, Cr3+
(Atomic numbers: Ti = 22, V = 23, Mn = 25, Cr = 24)
Answer the following:
1) Which ion is most stable in an aqueous solution and why?
2) Which ion is a strong oxidising agent and why?
3) Which ion is colourless and why?
Write balanced chemical equations for the conversion of `CrO_4^(2-)` to `Cr_2O_7^(2-)` in acidic medium and `Cr_2O_7^(2-)` to `CrO_4^(2-)`
in basic medium.
Explain why Zn2+ salts are white whereas Cu2+ salts are coloured.
Electronic configuration of Mn2+ is ____________.
Which of the following ions show higher spin only magnetic moment value?
(i) \[\ce{Ti^3+}\]
(ii) \[\ce{Mn2+}\]
(iii) \[\ce{Fe2+}\]
(iv) \[\ce{Co3+}\]
Transition elements form binary compounds with halogens. Which of the following elements will form \[\ce{MF3}\] type compounds?
(i) \[\ce{Cr}\]
(ii) \[\ce{Co}\]
(iii) \[\ce{Cu}\]
(iv) \[\ce{Ni}\]
Match the properties given in Column I with the metals given in Column II.
| Column I (Property) | Column II (Metal) | |
| (i) | An element which can show +8 oxidation state | (a) \[\ce{Mn}\] |
| (ii) | 3d block element that can show | (b) \[\ce{Cr}\] |
| upto +7 oxidation state | (c) \[\ce{Os}\] | |
| (iii) | 3d block element with highest melting point | (d) \[\ce{Fe}\] |
Mention any three processes where transition metals act as catalysts.
The element with atomic number 53 belongs to
The element with atomic number 46 belongs to
If enthalpies of formation of C2H4(g), CO2(g) and H2O(l) at 25°C and 1 atm pressure are 52, – 394 and – 286 kJ/mol respectively, the change in ethalpy for combustion of C2H4 is equal to
The complex showing a spin-span magnetic moment of 2.82 B.M. is :-
Agcl is soluble in NH4OH. The solubility is due to the information of:-
A complex in which dsp2 hybridisation takes place is ______.
In the ground state of atomic Fe (Z = 26), the spin-only magnetic moment is ______ × 10-1 BM.
(Round off to the nearest integer).
[Given: `sqrt3 = 1.73, sqrt2 = 1.41`]
Which of the following characteristics of transition metals is associated with their catalytic activity?
Account for the following:
Copper has an exceptionally positive `"E"_("M"^(2+)//"M")^0` value.
Write the ionic equation for reaction of KI with acidified KMnO4.
A pair of coloured ions is ______.
Explain the magnetic properties of d-block (or transition) elements.
The compounds of \[\ce{Ti^4+}\] ions are colourless due to ______.
Decide which of the following atomic numbers are the atomic numbers of the inner transition elements:
29, 59, 74, 95, 102, 104
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:
Oxidation states
