Chapter 3

The atomic number of the element unnilennium is : [Main Sep. 03, 2020 (I)] (a) 109 (b) 102 (c) 108 (d) 119

The set that contains atomic numbers of only transition elements, is : (a) \(37,42,50,64\) (b) \(21,25,42,72\) (c) \(9,17,34,38\) (d) \(21,32,53,64\)

The group number, number of valence electrons, and valency of an element with atomic number 15, respectively, are :(a) 16,5 and 2 (b) 15,5 and 3 (c) 16,6 and 3 (d) 15,6 and 2

The correct order of the ionic radii of \(\mathrm{O}^{2-}, \mathrm{N}^{3-}, \mathrm{F}^{-}, \mathrm{Mg}^{2+}, \mathrm{Na}^{+}\)and \(\mathrm{Al}^{3+}\) is : (a) \(\mathrm{N}^{3-}<\mathrm{O}^{2-}<\mathrm{F}^{-}<\mathrm{Na}^{+}<\mathrm{Mg}^{2+}<\mathrm{Al}^{3+}\) (b) \(\mathrm{Al}^{3+}<\mathrm{Na}^{+}<\mathrm{Mg}^{2+}<\mathrm{O}^{2-}<\mathrm{F}^{-}<\mathrm{N}^{3-}\) (c) \(\mathrm{Al}^{3+}<\mathrm{Mg}^{2+}<\mathrm{Na}^{+}<\mathrm{F}^{-}<\mathrm{O}^{2-}<\mathrm{N}^{3-}\) (d) \(\mathrm{N}^{3-}<\mathrm{F}^{-}<\mathrm{O}^{2-}<\mathrm{Mg}^{2+}<\mathrm{Na}^{+}<\mathrm{Al}^{3+}\)

The element with \(\mathrm{Z}=120\) (not yet discovered) will be an/a:(a) Inner- transition metal (b) Alkaline earth metal (c) Alkali metal (d) Transition metal

The elements with atomic numbers 101 and 104 belong to, respectively : (a) Group 11 and Group 4 (b) Actinoids and Group 6 (c) Actinoids and Group 4 (d) Group 6 and Actinoids

Similarity in chemical properties of the atoms of elements in a group of the periodic table is most closely related to:(a) atomic numbers (b) atomic masses (c) number of principal energy levels (d) number of valence electrons

The process that is NOT endothermic in nature is : (a) \(\mathrm{Ar}(\mathrm{g})+\mathrm{e}^{-} \rightarrow \mathrm{Ar}^{-}(\mathrm{g})\) (b) \(\mathrm{H}(\mathrm{g})+\mathrm{e}^{-} \rightarrow \mathrm{H}^{-}(\mathrm{g})\) (c) \(\mathrm{O}^{-}(\mathrm{g})+\mathrm{e}^{-} \rightarrow \mathrm{O}^{2-}(\mathrm{g})\) (d) \(\mathrm{Na}(\mathrm{g}) \rightarrow \mathrm{Na}^{+}(\mathrm{g})+\mathrm{e}^{-}\)

Which of the following has the maximum number of unpaired electrons? [1996-1 Mark] (a) \(\mathrm{Mg}^{2+}\) (b) \(\mathrm{Ti}^{3+}\) (c) \(\mathrm{V}^{3+}\) (d) \(\mathrm{Fe}^{2+}\)

The ionic radii of \(\mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Na}^{+}\)and \(\mathrm{Mg}^{2+}\) are in the order: (a) \(\mathrm{F}^{-}>\mathrm{O}^{2-}>\mathrm{Na}^{+}>\mathrm{Mg}^{2+}\) (b) \(\mathrm{O}^{2-}>\mathrm{F}^{-}>\mathrm{Na}^{+}>\mathrm{Mg}^{2+}\) (c) \(\mathrm{Mg}^{2+}>\mathrm{Na}^{+}>\mathrm{F}^{-}>\mathrm{O}^{2-}\) (d) \(\mathrm{O}^{2-}>\mathrm{F}^{-}>\mathrm{Mg}^{2+}>\mathrm{Na}^{+}\)

The statement that is not correct for the periodic classification of element is [1992-1 Mark] (a) The properties of elements are the periodic functions of their atomic numbers (b) Non-metallic elements are lesser in number than metallic elements (c) The first ionisation energies of elements along a period do not vary in a regular manner with increase in atomic number (d) For transition elements the \(d\)-subshells are filled with electrons monotonically with increase in atomic number.

Among the statements (I - IV), the correct ones are : (I) Be has smaller atomic radius compared to \(\mathrm{Mg}\). (II) Be has higher ionization enthalpy than Al. (III)Charge/radius ratio of Be is greater than that of Al. (IV) Both Be and Al form mainly covalent compounds. (a) (I), (II) and (IV) (b) (I), (III) and (IV) (c) (II), (III) and (IV) (d) (I), (II) and (III)

The atomic number of Unnilunium is

The five successive ionization enthalpies of an element are 800,2427 , 3658, 25024 and \(32824 \mathrm{~kJ} \mathrm{~mol}^{-1}\). The number of valence electrons in the element is : (a) 5 (b) 4 (c) 3 (d) 2

The statements that are true for the long form of the periodic table are: [1988 - 1 Mark] (a) it reflects the sequence of filling the electrons in the order of subenergy level \(\mathrm{s}, \mathrm{p}, \mathrm{d}\) and \(\mathrm{f}\). (b) it helps to predict the stable valency states of the elements (c) it reflects trends in physical and chemical properties of the elements (d) it helps to predict the relative ionicity of the bond between any two elements.

he statements that are true for the long form of the periodic table are: (a) it reflects the sequence of filling the electrons in the order of subenergy level \(\mathrm{s}, \mathrm{p}, \mathrm{d}\) and \(\mathrm{f}\). (b) it helps to predict the stable valency states of the elements (c) it reflects trends in physical and chemical properties of the elements (d) it helps to predict the relative ionicity of the bond between any two elements.

In general, the property (magnitudes only) that shows an opposite trend in comparison to other properties across a period is : (a) Ionization enthalpy (b) Electronegativity (c) Electron gain enthalpy (d) Atomic radius

Three elements \(\mathrm{X}, \mathrm{Y}\) and \(\mathrm{Z}\) are in the \(3^{\text {rt }}\) period of the periodic table. The oxides of \(X, Y\) and \(Z\), respectively, are basic, amphoteric and acidic. The correct order of the atomic numbers of \(X, Y\) and \(Z\) is : (a) \(\mathrm{Z}<\mathrm{Y}<\mathrm{X}\) (b) \(\mathrm{X}<\mathrm{Y}<\mathrm{Z}\) (c) \(\mathrm{X}<\mathrm{Z}<\mathrm{Y}\) (d) \(\mathrm{Y}<\mathrm{X}<\mathrm{Z}\)

B has a smaller first ionization enthalpy than Be. Consider the following statements: (I) it is easier to remove \(2 p\) electron than \(2 s\) electron (II) \(2 p\) electron of \(\mathrm{B}\) is more shielded from the nucleus by the inner core of electrons than the \(2 s\) electrons of \(\mathrm{Be}\) (III) \(2 s\) electron has more penetration power than \(2 p\) electron (IV) atomic radius of \(\mathrm{B}\) is more than \(\mathrm{Be}\) (atomic number \(\mathrm{B}=5, \mathrm{Be}=4\) ) The correct statements are: (a) (I), (II) and (IV) (b) (II), (III) and (IV) (c) (I), (II) and (III) (d) (I), (III) and (IV)

The acidic, basic and amphoteric oxides, respectively, are: (a) \(\mathrm{Na}_{2} \mathrm{O}, \mathrm{SO}_{3}, \mathrm{Al}_{2} \mathrm{O}_{3}\) (b) \(\mathrm{Cl}_{2} \mathrm{O}, \mathrm{CaO}, \mathrm{P}_{4} \mathrm{O}_{10}\) (c) \(\mathrm{N}_{2} \mathrm{O}_{3}, \mathrm{Li}_{2} \mathrm{O}, \mathrm{Al}_{2} \mathrm{O}_{3}\) (d) \(\mathrm{MgO}, \mathrm{Cl}_{2} \mathrm{O}, \mathrm{Al}_{2} \mathrm{O}_{3}\)

The first and second ionisation enthalpies of a metal are 496 and 4560 kJ \(\mathrm{mol}^{-1}\), respectively. How many moles of \(\mathrm{HCl}\) and \(\mathrm{H}_{2} \mathrm{SO}_{4}\), respectively, will be needed to react completely with 1 mole of the metal hydroxide? (a) 1 and 1 (b) 2 and \(0.5\) (c) 1 and 2 (d) 1 and \(0.5\)

The first ionization energy (in \(\mathrm{kJ} / \mathrm{mol}\) ) of \(\mathrm{Na}, \mathrm{Mg}, \mathrm{Al}\) and \(\mathrm{Si}\) respectively, are: (a) \(496,737,577,786\) (b) \(496,577,737,786\) (c) \(786,737,577,496\) (d) \(496,577,786,737\)

The increasing order of the atomic radii of the following elements is: (i) \(\mathrm{C}\) (ii) \(\mathrm{O}\) (iii) F (iv) \(\mathrm{Cl}\) (v) \(\mathrm{Br}\) (a) \((\mathrm{ii})<(\mathrm{iii})<(\mathrm{iv})<(\mathrm{i})<(\mathrm{v})\) (b) \((\mathrm{iv})<(\mathrm{iii})<(\mathrm{ii})<(\mathrm{i})<(\mathrm{v})\) (c) (iii) \(<(i i)<(i)<(i v)<(v)\) (d) \((\mathrm{i})<(\mathrm{ii})<(\mathrm{iii})<(\mathrm{iv})<(\mathrm{v})\)

The electron gain enthalpy (in \(\mathrm{kJ} / \mathrm{mol}\) ) of fluorine, chlorine, bromine and iodine, respectively, are: (a) \(-296,-325,-333\) and \(-349\) (b) \(-349,-333,-325\) and \(-296\) (c) \(-333,-349,-325\) and \(-296\) (d) \(-333,-325,-349\) and \(-296\)

Within each pair of elements \(\mathrm{F} \& \mathrm{Cl}, \mathrm{S} \& \mathrm{Se}\), and \(\mathrm{Li}\) \& \(\mathrm{Na}\), respectively, the elements that release more energy upon an electron gain are: (a) \(\mathrm{Cl}\), Se and \(\mathrm{Na}\) (b) \(\mathrm{Cl}, \mathrm{S}\) and \(\mathrm{Li}\) (c) \(\mathrm{F}, \mathrm{S}\) and \(\mathrm{Li}\) (d) F, Se and \(\mathrm{Na}\)

In comparison to boron, berylium has: (a) lesser nuclear charge and lesser first ionisation enthalpy. (b) greater nuclear charge and lesser first ionisation enthalpy. (c) greater nulear charge and greater first ionisation enthalpy. (d) lesser nuclear charge and greater first ionisation enthalpy.

The correct order of the atomic radii of \(\mathrm{C}, \mathrm{Cs}, \mathrm{Al}\), and \(\mathrm{S}\) is : (a) \(\mathrm{C}<\mathrm{S}<\mathrm{A} 1<\mathrm{Cs}\) (b) \(\mathrm{S}<\mathrm{C}<\mathrm{Cs}<\mathrm{Al}\) (c) \(\mathrm{S}<\mathrm{C}<\mathrm{Al}<\mathrm{Cs}\) (d) \(\mathrm{C}<\mathrm{S}<\mathrm{Cs}<\mathrm{Al}\)

The \(71^{\text {st }}\) electron of an element \(\mathrm{X}\) with an atomic number of 71 enters into the orbital: (a) \(6 p\) (b) \(4 f\) (c) \(5 d\) (d) \(6 s\)

In general, the properties that decrease and increase down a group in the periodic table, respectively, are: (a) atomic radius and electronegativity. (b) electron gain enthalpy and electronegativity. (c) electronegativity and atomic radius.

The correct order of electron affinity is: (a) \(\mathrm{O}>\mathrm{F}>\mathrm{Cl}\) (b) \(\mathrm{F}>\mathrm{O}>\mathrm{Cl}\) (c) \(\mathrm{F}>\mathrm{Cl}>\mathrm{O}\) (d) \(\mathrm{Cl}>\mathrm{F}>\mathrm{O}\)

Both lithium and magnesium display several similar properties due to the diagonal relationship; however, the one which is incorrect is : (a) Both form basic carbonates (b) Both form soluble bicarbonates (c) Both form nitrides (d) Nitrates of both Li and Mg yield \(\mathrm{NO}_{2}\) and \(\mathrm{O}_{2}\) on heating

The group having isoelectronic species is: (a) \(\mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Na}^{+}, \mathrm{Mg}^{2+}\) (b) \(\mathrm{O}^{-}, \mathrm{F}^{-}, \mathrm{Na}, \mathrm{Mg}^{+}\) (c) \(\mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Na}, \mathrm{Mg}^{2+}\) (d) \(\mathrm{O}^{-}, \mathrm{F}^{-}, \mathrm{Na}^{+}, \mathrm{Mg}^{2+}\)

Which of the following atoms has the highest first ionization energy? (a) \(\mathrm{K}\) (b) \(\mathrm{Sc}\) (c) \(\mathrm{Rb}\) (d) \(\mathrm{Na}\)

The following statements concern elements in the periodic table. Which of the following is true? [Main Online April 10, 2016] (a) For Group 15 elements, the stability of \(+5\) oxidation state increases down the group (b) Elements of Group 16 have lower ionization enthalpy values compared to those of Group 15 in the corresponding periods. (c) The Group 13 elements are all metals (d) All the elements in Group 17 are gases.

The ionic radii (in \(\AA\) ) of \(\mathrm{N}^{3-}, \mathrm{O}^{2-}\) and \(\mathrm{F}^{-}\)are respectively : (a) \(1.71,1.40\) and \(1.36\) (b) \(1.71,1.36\) and \(1.40\) (c) \(1.36,1.40\) and \(1.71\) (d) \(1.36,1.71\) and \(1.40\)

In the long form of the periodic table, the valence shell electronic configuration of \(5 s^{2} 5 p^{4}\) corresponds to the element present in : (a) Group 16 and period 6 (b) Group 17 and period 6 (c) Group 16 and period 5 (d) Group 17 and period 5

Which of the following series correctly represents relations between the elements from \(\mathrm{X}\) to \(\mathrm{Y}\) ? \(\mathrm{X} \rightarrow \mathrm{Y}\) (a) \({ }_{3} \mathrm{Li} \rightarrow{ }_{19} \mathrm{~K}\) Ionization enthalpy increases (b) \({ }_{9} \mathrm{~F} \rightarrow{ }_{35} \mathrm{Br}\) Electron gain enthalpy (negative sign) increases (c) \({ }_{6} \mathrm{C} \rightarrow{ }_{32} \mathrm{Ge}\) Atomic radii increases (d) \({ }_{18} \mathrm{Ar} \rightarrow{ }_{54} \mathrm{Xe}\) Noble character increases

Which of the following arrangements represents the increasing order (smallest to largest) of ionic radii of the given species \(\mathrm{O}^{2-}, \mathrm{S}^{2-}, \mathrm{N}^{3}, \mathrm{P}^{3-}\) ? (a) \(\mathrm{O}^{2-}<\mathrm{N}^{3-}<\mathrm{S}^{2-}<\mathrm{P}^{3-}\) (b) \(\mathrm{O}^{2-}<\mathrm{P}^{3-}<\mathrm{N}^{3-}<\mathrm{S}^{2-}\) (c) \(\mathrm{N}^{3-}<\mathrm{O}^{2-}<\mathrm{P}^{3-}<\mathrm{S}^{2-}\) (d) \(\mathrm{N}^{3-}<\mathrm{S}^{2-}<\mathrm{O}^{2-}<\mathrm{P}^{3-}\)

Which of the following represents the correct order of increasing first ionization enthalpy for \(\mathrm{Ca}, \mathrm{Ba}, \mathrm{S}\), Se and \(\mathrm{Ar}\) ? (a) \(\mathrm{Ca}<\mathrm{S}<\mathrm{Ba}<\mathrm{Se}<\mathrm{Ar}\) (b) \(\mathrm{S}<\mathrm{Se}<\mathrm{Ca}<\mathrm{Ba}<\mathrm{Ar}\) (c) \(\mathrm{Ba}<\mathrm{Ca}<\mathrm{Se}<\mathrm{S}<\mathrm{Ar}\) (d) \(\mathrm{Ca}<\mathrm{Ba}<\mathrm{S}<\mathrm{Se}<\mathrm{Ar}\)

The order of increasing sizes of atomic radii among the elements \(\mathrm{O}\), S, Se and As is : [Main Online April 22, 2013] (a) \(\mathrm{As}<\mathrm{S}<\mathrm{O}<\mathrm{Se}\) (b) \(\mathrm{Se}<\mathrm{S}<\mathrm{As}<\mathrm{O}\) (c) \(\mathrm{O}<\mathrm{S}<\mathrm{As}<\mathrm{Se}\) (d) \(\mathrm{O}<\mathrm{S}<\mathrm{Se}<\mathrm{As}\)

Identify the correct order of acidic strengths of \(\mathrm{CO}_{2}, \mathrm{CuO}, \mathrm{CaO}, \mathrm{H}_{2} \mathrm{O}\) (a) \(\mathrm{CaO}<\mathrm{CuO}<\mathrm{H}_{2} \mathrm{O}<\mathrm{CO}_{2}\) (b) \(\mathrm{H}_{2} \mathrm{O}<\mathrm{CuO}<\mathrm{CaO}<\mathrm{CO}_{2}\) (c) \(\mathrm{CaO}<\mathrm{H}_{2} \mathrm{O}<\mathrm{CuO}<\mathrm{CO}_{2}\) (d) \(\mathrm{H}_{2} \mathrm{O}<\mathrm{CO}_{2}<\mathrm{CaO}<\mathrm{CuO}\)

Amongst \(\mathrm{H}_{2} \mathrm{O}, \mathrm{H}_{2} \mathrm{~S}, \mathrm{H}_{2} \mathrm{Se}\) and \(\mathrm{H}_{2} \mathrm{Te}\), the one with the highest boiling point is [2000S] (a) \(\mathrm{H}_{2} \mathrm{O}\) because of hydrogen bonding (b) \(\mathrm{H}_{2}\) Te because of higher molecular weight (c) \(\mathrm{H}_{2} \mathrm{~S}\) because of hydrogen bonding (d) \(\mathrm{H}_{2} \mathrm{Se}\) because of lower molecular weight

Which has most stable \(+2\) oxidation state : (a) \(\mathrm{Sn}\) (b) \(\mathrm{Pb}\) (c) \(\mathrm{Fe}\) (d) Ag

Amongst the following elements (whose electronic configurations are given below), the one having the highest ionization energy is: (a) \([\mathrm{Ne}] 3 s^{2} 3 p^{1}\) (b) \([\mathrm{Ne}] 3 s^{2} 3 p^{3}\) (c) \([\mathrm{Ne}] 3 s^{2} 3 p^{2}\) (d) \([\mathrm{Ne}] 3 d^{10} 4 s^{2} 4 p^{3}\)

Which one of the following is the strongest base? (a) \(\mathrm{AsH}_{3}\) (b) \(\mathrm{NH}_{3}\) (c) \(\mathrm{PH}_{3}\) (d) \(\mathrm{SbH}_{3}\)

Which one of the following is the smallest in size? (a) \(\mathrm{N}^{3-}\) (b) \(\mathrm{O}^{2-}\) (c) \(\mathrm{F}^{-}\) (d) \(\mathrm{Na}^{+}\)

The first ionisation potential of \(\mathrm{Na}, \mathrm{Mg}, \mathrm{Al}\) and \(\mathrm{Si}\) are in the order (a) \(\quad \mathrm{Na}<\mathrm{Mg}>\mathrm{Al}<\mathrm{Si}\) (b) \(\quad \mathrm{Na}>\mathrm{Mg}>\mathrm{Al}>\mathrm{Si}\) (c) \(\quad \mathrm{Na}<\mathrm{Mg}<\mathrm{Al}<\mathrm{Si}\) (d) \(\mathrm{Na}>\mathrm{Mg}>\mathrm{Al}<\mathrm{Si}\)

The electronegativity of the following elements increases in the order (a) \(\mathrm{C}, \mathrm{N}, \mathrm{Si}, \mathrm{P}\) (b) \(\mathrm{N}, \mathrm{Si}, \mathrm{C}, \mathrm{P}\) (c) Si, P, C, N (d) \(\mathrm{P}, \mathrm{Si}, \mathrm{N}, \mathrm{C}\)

The first ionisation potential in electron volts of nitrogen and oxygen atoms are respectively given by (a) \(14.6,13.6\) (b) \(13.6,14.6\) (c) \(13.6,13.6\) (d) \(14.6,14.6\)

Atomic radii of fluorine and neon in Ångstorm units are respectively given by (a) \(0.72,1.60\) (b) \(1.60,1.60\) (c) \(0.72,0.72\) (d) None of these values