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The elements in groups 3–12 are known as d-block elements. D-orbitals are gradually filled in these elements as periods increase. The f-block elements have been separated from the rest of the periodic table at the bottom. The elements in the f-block have 4 and 5 f orbitals that are gradually filled.
Question 1: The oxidation number of gold is
(a) +1
(b) 0
(c) -1
(d) all of these
Answer: (a) +1.
Question 2: What is the shape of the d-orbital?
(a) spherical
(b) dumb bell
(c) double dumb bell
(d) none of these
Answer: (c) double dumb bell because There are three p orbitals that differ in orientation along a three-dimensional axis.
Question 3: The electrical configuration of the alkaline earth element is
(a) ns2
(b) ns1
(c) np6
(d) ns0
Answer: (a)ns2. Because all alkaline earth metals contain two electrons in their valence shell, they must lose two electrons to produce +2 cations.
Question 4: Lanthanide contraction is caused by an increase in
(a) atomic number
(b) effective nuclear charge
(c) atomic radius
(d) valence electrons
Answer: (b) effective nuclear charge because From lanthanum through yttrium, the size of the atoms and ions of rare earth elements has steadily decreased as the atomic number has increased.
Question 5: Which of the following is the symbol for green vitriol?
(a) FeSO4 7H2O
(b) CuSO4 5H2O
(c) CaSO4 2H2O
(d) None of these
Answer: (a) FeSO4 .7H2O
Question 6: Which group of elements do transition elements belong to?
(a) p-block
(b) s-block
(c) d-block
(d) f-block
Answer: (c) d-block because Transition elements are found in groups 3-12 of the periodic table.
Question 7: Which of the following is the most common element in the earth’s crust?
(a) Si
(b) Al
(c) Zn
(d) Fe
Answer: (a) Si
Question 8: Which of the following is a diamagnetic ion?
(a) Co2+
(b) Ni2+
(c) Cu2+
(d) Zn2+
Answer: (d) Zn2+
Because there are no unpaired electrons in this substance, and it is not attracted to a magnetic field.
Question 9: Which of the following is not a part of the first transition series?
(a) Iron
(b) Chromium
(c) Magnesium
(d) Nickel
Answer: (c) Magnesium.
Question 10: What is the correct order of EM2+/M° values with a negative sign for the four elements Cr, Mn, Fe, and Co?
( a) Fe > Mn > Cr > Co
(b) Cr > Mn > Fe > Co
(c) Mn > Cr > Fe > Co
(d) Cr > Fe > Mn > Co
Answer: (c) Mn > Cr > Fe > Co
Question 11: The total number of unpaired electrons in Mn3+, Cl3+, and V3+ gaseous species is, and the most stable species is
( a) 4, 3 and 2; V3+
(b) 3, 3 and 2; Cr3+
(c) 4, 3 and 2; Cr3+
(d) 3, 3 and 3; Mn3+
Answer: (c) 4, 3 and 2; Cr3+
Question 12: Why is Fe3+ ion more stable than Fe2+ ion?
(a) more the charge on the atom, more is its stability
(b) configuration of Fe2+ is 3d5while Fe3+ is 3d5
(c) Fe2+ has a larger size than Fe3+
(d) Fe3+ ions are coloured hence more stable
Answer: (b) configuration of Fe2+ is 3d5 while Fe3+is 3d5
With the help of the electronic configuration, this is described. There are five 3d half-filled orbitals in Fe3+ ions, making it more symmetrical than Fe2+. In the Fe2+ ion, there are four 3d half-filled orbitals and one filled orbital.
Question 13: The colour of transition metal ions is caused by absorption of a specific wavelength. This results in
( a) d-s transition
(b) s-s transition
(c) s-t/transition
(d) d-d transition
Answer: (d) d-d transition
Question 14: Which of the following groups contains coloured ions?
1. Cu–. 2. Ti4- 3. Co2+ 4. Fe2-
(a) 1, 2, 3, 4
(b) 3, 4
(c) 2, 3
(4) 1, 2
Answer: (b) 3, 4
Question 15: What is the sequence of the melting points of Cu, Ag, and Au?
(a )Cu > Ag > Au
(b) Cu >Au > Ag
(c) Au > Ag > Cu
(d) Ag > Au > Cu
Answer: (b) Cu >Au > Ag.
Question 16: Which of the following pairs of ions has a more stable lower oxidation state in aqueous solution than the other
(a) Ti+, Ti3+
(b)Cu+, Cu3+
(c) Cr2+, Cr3+
(d) V2+, VO2+ (V4)
Answer: (a) Ti+ ,Ti3+
Question 17:Which of the following pairs of ions has the same electrical configuration?
(a) Cu2+, Cr2+
(b) Fe3+, Mn2+
(c) Co3+, Ni3+
(d) Sc3+, Cr3+
Answer: (b) Fe3+, Mn2+
Question 18: The melting point of copper is greater than that of zinc because
(a) Copper has a bcc structure
(b) Copper has a larger atomic volume
(c) Copper electrons are involved in metallic bonding
(d) Metallic bonding involves both the s and d electrons of copper.
Answer: (c) Copper electrons are involved in metallic bonding
Question 19: Zr and Hf have almost equal atomic and ionic radii because of
(a) diagonal relationship
(b) lanthanoid contraction
(c) actinoid contraction
(d) belonging to the same group
Answer: (b) lanthanoid contraction
The positive charge on the nucleus grows by +1 unit as the atomic number of the Lanthanide series increases, and one additional electron enters the same 4f subshell.
Question 20: Which of the following does not constitute an amphoteric ion?
(a) Al3+
(b) Cr3+
(c) Fe3+
(d) Zn2+
Answer: (c) Fe3+
Question 21: What happens when potassium iodide reacts with an acidic potassium dichromate solution?
(a) It releases iodine
(a) The formation of potassium sulphate
(c) The formation of chromium sulphate
(d) All of the aforementioned products are created.
Answer: (d) All of the aforementioned products are created
Question 22. How many moles of KMnO4 are required to completely react with one mole of ferrous oxalate in acidic solution?
( a) 3/5
(b) 2/5
(c) 4/5
(d) 1
Answer: (a) 3/5
Question 23: Acidified potassium dichromate combines with potassium iodide to form I2. What is the chromium oxidation state in the reaction products?
(a) +4
(b) +6
(c) +3
(d) +2
Answer: (c) +3
Question 24: In a reaction with excess KI, one mole of acidified K2Cr3+O will liberate………….. mole(s) of I2
(a) 6
(b) 1
(c) 7
(d) 2
Answer: (a) 6
Question 25: In the dichromate anion (Cr2O72-),
(a) all Cr – O bonds are equal.
(a) All Cr – O bonds are the same (b) 6 Cr – O bonds are the same.
(c) Three Cr–O bonds are equivalent.
(d) There are no comparable bonds in Cr2O2-7.
Answer: (b) 6 Cr – O bonds are equivalent.
