Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d⁵. What is its atomic number?
(a) 25
(b) 26
(c) 27
(d) 24
(a) 25
(b) 26
(c) 27
(d) 24
(b) 26
Explanation : It is formed by the loss of 3 electrons, the configuration of element X is [Ar] 3d⁶ 4s². Therefore, Atomic number = 26.
Explanation : It is formed by the loss of 3 electrons, the configuration of element X is [Ar] 3d⁶ 4s². Therefore, Atomic number = 26.
Metallic radii of some transition elements are given below. Which of these elements will have highest density?
What are the transition elements ? Write two characteristics of the transition elements.
Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group number.
Write the formula of an oxo-anion of Chromium (Cr) in which it shows the oxidation state equal to its group number.
Explain the following observation :
Most of the transition metal ions exhibit characteristic colour in aqueous solution.
Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with (i) an iodide (ii) H₂S.
When Cu²⁺ ion is treated with KI, a white precipitate is formed. Explain the reaction with the help of chemical equation.
The idea that promoted to Bartlett to prepare first ever compound of Noble gases was
a) Low bond dissociation enthalpy of F-F bond in \(F_2\).
b) High bond enthalpy of Xe-F bond.
c) Ionization enthalpies of \(O_2\) and Xe are almost same.
d) None of the above.
Aryl halides can not be prepared by the reaction of arylalcohols with \(PCl_3\), \(PCl_5\) or \(SOCl_2\) because :
(a) phenols are highly stable compounds.
(b) carbon-oxygen bond in phenols has a partial doublebond character.
(c) carbon-oxygen bond is highly polar
(d) all of these
Chlorine water on standing loses its yellow colour due to the formation of
a) Cl and HOCl.
b) HCl and HOCl.
c) HOCl and \(HOCl_2\).
d) HCl and \(HOCl_2\).
The electronic configuration of Cu(II) is 3d⁹ whereas that of Cu(I) is 3d¹⁰. Which of the following is correct?
(a) Cu(II) is more stable
(b) Cu(II) is less stable
(c) Cu(I) and Cu(II) are equally stable
(d) Stability of Cu(I) and Cu(II) depends on nature of copper salts
Which of the following is not true about the ionic solids?
(A) Bigger ions form the close packed structure.
(B) Smaller ions occupy either the tetrahedral or the octahedral voids depending upon their size.
(C) Occupation of all the voids is not necessary.
(D) The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids.
The lowest boiling point of helium is due to its
a) Inertness
b) Gaseous nature
c) Weak van der Waals force between atoms
d) electronic configuration