Metallic radii of some transition elements are given below. Which of these elements will have highest density?
(a) Fe
(b) Ni
(c) Co
(d) Cu
(a) Fe
(b) Ni
(c) Co
(d) Cu
(d) Cu
Explanation: In periodic table when moving from left to right along period, its metallic radius decreases and mass increases. Decrease in metallic radius coupled with increase in atomic mass which results in the increase in density of metal. Therefore, among above four options, copper belongs to right side of periodic table in transition metal and it has the highest density.
Explanation: In periodic table when moving from left to right along period, its metallic radius decreases and mass increases. Decrease in metallic radius coupled with increase in atomic mass which results in the increase in density of metal. Therefore, among above four options, copper belongs to right side of periodic table in transition metal and it has the highest density.
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
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.
How would you account for the following ? Many of the transition elements are known to form interstitial compounds.
Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with (i) an iodide (ii) H₂S.
Assign the reason for the following :
Copper (I) ion is not known in aqueous solution.
Which of the following compounds will be most easily attacked by an electrophile?
Which statement is incorrect about peptide bond?
(a) C-N bond length in proteins is longer than usual bond length of C-N bond.
(b) Spectroscopic analysis shows planar structure of -CO-NH- group
(c) C-N bond length in proteins is smaller than usual bond length of C-N bond
(d) None of the above
Which of the following statements is not true about the hexagonal close packing?
(A) The coordination number is 12.
(B) It has 74% packing efficiency.
(C) Tetrahedral voids of the second layer are covered by the spheres of the third layer.
(D) In this arrangement spheres of the fourth layer are exactly aligned with those of the first layer.
Graphite cannot be classified as __________.
(A) Conducting solid
(B) Network solid
(C) Covalent solid
(D) Ionic solid
Equimolar solutions in the same solvent have-
(a) Same boiling point but different freezing point
(b) Same freezing point, but different boiling point
(c) Same boiling and same freezing point
(d) Different boiling and different freezing points
Assertion: Glycine must be taken through diet.
Reason: It is essential amino acid.
A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.
The total number of tetrahedral voids in the face centred unit cell is _____.
(A) 6
(B) 8
(C) 10
(D) 12