Which of the following elements have half-filled f-orbitals in their ground state? (Given : atomic number $\mathrm{Sm}=62 ; \mathrm{Eu}=63 ; \mathrm{...

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R) Assertion (A): The first ionization enthalp...

The correct increasing order of the ionic radii is

Bond dissociation energy of "E-H" bond of the "$\mathrm{H}_{2} \mathrm{E}$ " hydrides of group 16 elements (given below), follows order. A. $\mathrm{O...

Match List I with List II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family...

Given below are two statements : Statement I : The decrease in first ionization enthalpy from B to Al is much larger than that from Al to Ga. Statemen...

Inert gases have positive electron gain enthalpy. Its correct order is

The first ionization enthalpy of Na, Mg and Si, respectively, are : 496, 737 and $$786 \mathrm{~kJ} \mathrm{~mol}^{-1}$$. The first ionization enthalp...

In which of the following pairs, electron gain enthalpies of constituent elements are nearly the same or identical? (A) Rb and Cs (B) Na and K (C) Ar ...

The incorrect statement is

Given two statements below : Statement I : In $$\mathrm{Cl}_{2}$$ molecule the covalent radius is double of the atomic radius of chlorine. Statement I...

The first ionization enthalpies of Be, B, N and O follow the order

The IUPAC nomenclature of an element with electronic configuration [Rn] $$5 \mathrm{f}^{14} 6 \mathrm{d}^{1} 7 \mathrm{s}^{2}$$ is :

The correct order of electron gain enthalpy ($$-$$ ve value) is :

Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R. Assertion A : The first ionization enthalpy for ...

The electronic configuration of Pt (atomic number 78) is:

Element "E" belongs to the period 4 and group 16 of the periodic table. The valence shell electron configuration of the element, which is just above "...

The correct order of increasing ionic radii is

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : The ionic radii of O2$$-$$ ...

The correct order of electron gain enthalpies of Cl, F, Te and Po is

Identify the element for which electronic configuration in +3 oxidation state is [Ar]3d5 :

The Eu2+ ion is a strong reducing agent in spite of its ground state electronic configuration (outermost) : [Atomic number of Eu = 63]

Match List - I with List - II : List - I(Metal Ion) List - II(Group of Qualitative analysis) (a) $$M{n^{2 + }}$$...

Which one of the following lanthanides exhibits +2 oxidation state with diamagnetic nature ? (Given Z for Nd = 60, Yb = 70, La = 57, Ce = 58)

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) : Metallic character decreases...

Choose the correct statement from the following :

The correct order of ionic radii for the ions, P3$$-$$, S2$$-$$, Ca2+, K+, Cl$$-$$ is :

Which one of the following is used to remove most of plutonium from spent nuclear fuel?

In which one of the following molecules strongest back donation of an electron pair from halide to boron is expected?

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) : Barium carbonate is insolubl...

Chalcogen group elements are :

The correct order of first ionisation enthalpy is :

The ionic radii of F$$-$$ and O2$$-$$ respectively are 1.33$$\mathop A\limits^o $$ and 1.4$$\mathop A\limits^o $$, while the covalent radius of N is 0...

The ionic radii of K+, Na+, Al3+ and Mg2+ are in the order:

Which one of the following statements for D.I. Mendeleeff, is incorrect?

The set having ions which are coloured and paramagnetic both is -

The first ionization energy of magnesium is smaller as compared to that of elements X and Y, but higher than that of Z. The elements X, Y and Z, respe...

The common positive oxidation states for an element with atomic number 24, are :

The absolute value of the electron gain enthalpy of halogens satisfies :

The characteristics of elements X, Y and Z with atomic numbers, respectively, 33, 53 and 83 are :

Identify the elements X and Y using the ionisation energy values given below : Ionization energy (kJ/mol) 1$${st}$$...

Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R :Assertion A : Size of Bk3+ ion is less than Np3+...

The correct order of electron gain enthalpy is :

Match List - I with List - II. List I Electronic configuration List II $${\Delta _i}H$$ in kJ $$mo{l^{ - 1}}$$ (a) ...

The correct order of bond dissociation enthalpy of halogens is :

What is the correct order of the following elements with respect to their density?

Consider the elements Mg, Al, S, P and Si, the correct increasing order of their first ionization enthalpy is :

The correct order of the ionic radii of O2–, N3–, F– , Mg2+, Na+ and Al3+ is :

The incorrect statement(s) among (a) - (c) is (are) (a) W(VI) is more stable than Cr(VI). (b) In the presence of HCl, permanganate titrations provide ...

The elements with atomic numbers 101 and 104 belong to, respectively :

The ionic radii of O2–, F–, Na+ and Mg2+ are in the order :

Among the statements (I – IV), the correct ones are: (I) Be has smaller atomic radius compared to Mg. (II) Be has higher ionization enthalpy than Al. ...

Consider the hypothetical situation where the azimuthal quantum number, $$l$$, takes values 0, 1, 2, ....., n + 1, where n is the principal quantum nu...

The five successive ionization enthalpies of an element are 800, 2427, 3658, 25024 and 32824 kJ mol–1. The number of valence electrons in the element ...

The atomic number of the element unnilennium is :

Three elements X, Y and Z are in the 3rd period of the periodic table. The oxides of X, Y and Z, respectively, are basic, amphoteric and acidic. The c...

In general the property (magnitudes only) that show an opposite trend in comparison to other properties across a period is

The first and second ionisation enthalpies of a metal are 496 and 4560 kJ mol–1, respectively. How many moles of HCl and H2SO4, respectively, will be ...

B has a smaller first ionization enthalpy than Be. Consider the following statements : (I) It is easier to remove 2p electron than 2s electron (II) 2p...

The acidic, basic and amphoteric oxides, respectively, are :

The electronic configurations of bivalent europium and trivalent cerium are (atomic number : Xe = 54, Ce = 58, Eu = 63)

The increasing order of the atomic radii of the following elements is :- (a) C (b) O (c) F (d) Cl (e) Br

The third ionization enthalpy is minimum for :

The first ionization energy (in kJ/mol) of Na, Mg, Al and Si respectively, are :

Within each pair of elements F & Cl, S & Se, and Li & Na, respectively, the elements that release more energy upon and electron gain are :

The atomic radius of Ag is closed to :

The electron gain enthalpy (in KJ/mol) of fluorine, chlorine, bromine and iodine, respectively are:

Among the following, the energy of 2s orbital is lowest in :

The pair that has similar atomic radii is :

In comparison to boron, berylium has :

The correct sequence of thermal stability of the following carbonates is :

The highest possible oxidation states of uranium and plutonium, respectively are

The correct order of the first ionization enthalpies is :

The correct order of catenation is :

The element having greatest difference between its first and second ionization energies, is :

The IUPAC symbol for the element with atomic number 119 would be :

The correct order of hydration enthapies of alkali metal ions is :

The lathanide ion that would show colour is :

The size of the iso-electronic species Cl–,  Ar and Ca2+ is affected by :

The correct order of atomic radii is -

The element with Z = 120 (not yet discovered) will be an/a -

The correct option with respect to the Pauling electronegativity values of the element is :

The relative stability of +1 oxidation state of group 13 elements follows the order :

The correct order of the atomic radii of C, Cs, Al, and S is :

The 71st electron of an element X with an atomic number of 71 enters into the orbital;

The electronegativity of aluminium is similar to :

The effect of lanthanoid contraction in the lanthanoid series of elements by and large means :

When the first electron gain enthalpy $$\left( {{\Delta _{eg}}H} \right)$$ of oxygen is $$-$$ 141 kJ/mol, its second electron gain enthalpy is :

In general, the properties that decrease and increase down a group in the periodic table, respectively, are :

Aluminium is usually found in +3 oxidation state. In contrast, thallium exists in + 1 and + 3 oxidation states. This is due to :

The correct order of electron affinity is :

For Na+, Mg2+, F- and O2-; the correct order of increasing ionic radii is :

The electronic configuration with the highest ionization enthalpy is :

Consider the following ionization enthalpies of two elements 'A' and 'B' . .tg {border-collapse:collapse;border-spacing:0;} .tg td{font-family:Arial...

The following statements concern elements in the periodic table. Which of the following is true ?

The ionic radii (in Å) of N3–, O2– and F– are respectively:

Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar?

The first ionization potential of Na is 5.1 eV. The value of electron gain enthalpy of Na+ will be:

The increasing order of the ionic radii of the given isoelectronic species is :

Which one of the following order represents the correct sequence of the increasing basic nature of the given oxides ?

Outer electronic configuration of Gd (Atomic no : 64) is -

The correct sequence which shows decreasing order of the ionic radii of the elements is

In which of the following arrangements, the sequence is not strictly according to the property written against it

The set representing the correct order of ionic radius is :

Following statements regarding the periodic trends of chemical reactivity of the alkali metals and the halogens are given. Which of these statements g...

Which of the following oxides is amphoteric in character?

In which of the following arrangements the order is NOT according to the property indicated against it?

Which one of the following ions has the highest value of ionic radius?

Among Al2O3, SiO2, P2O3 and SO2 the correct order of acid strength is

The formation of the oxide ion O2-(g) requires first an exothermic and then an endothermic step as shown below O(g) + e- = $$O_{(g)}^{-}$$ $$\Delta $...

According to the Periodic Law of elements, the variation in properties of elements is related to their

Which one of the following is an amphoteric oxide?

The reduction in atomic size with increase in atomic number is a characteristic of elements of

The atomic numbers of Vanadium (V), Chromium (cr), Manganese (Mn) and Iron (Fe), respectively, $$23,24,25$$ and $$26$$. Which one of these may be expe...

The correct order of ionic radius is

$$C{e^{ + 3}},\,\,L{a^{ + 3}},\,\,P{m^{ + 3}}\,\,$$ and $$Y{b^{ + 3}}\,\,$$ have ionic radial in the increasing order as

Total number of acidic oxides among $$\mathrm{N_2O_3,NO_2,N_2O,Cl_2O_7,SO_2,CO,CaO,Na_2O}$$ and $$\mathrm{NO}$$ is ____________.

The number of f electrons in the ground state electronic configuration of Np (Z = 93) is ___________. (Nearest integer)

These are physical properties of an element(A) Sublimation enthalpy(B) Ionisation enthalpy(C) Hydration enthalpy(D) Electron gain enthalpyThe total nu...

The number of 4f electrons in the ground statement electronic configuration of Gd2+ is ___________. [Atomic number of Gd = 64]

Number of electrons present in 4f orbital of Ho3+ ion is ____________. (Given Atomic No. of Ho = 67)

Number of amphoteric compounds among the following is ________. (A) BeO (B) BaO (C) Be(OH)2 (D) Sr(OH)2

The atomic number of Unnilunium is _______.

Which of the following pair is not isoelectronic species? (At. no. Sm, 62; Er, 68; Yb, 70; Lu, 71; Eu, 63; Tb, 65; Tm, 69)