and for Mg are 178 Kcal mol–1 and 348 Kcal , respectively. The energy required for the reaction, will be:
1. +170 Kcal
2. +526 Kcal
3. –170 Kcal
4. –526 Kcal
Incorrect statement about characteristics regarding halogens is :
1. Ionization energy decreases with increase in atomic number.
2. Electronegativity decreases with increase in atomic number.
3. Electron affinity decreases with increase in atomic number.
4. Enthalpy of fusion increases with increase in atomic number.
The process requiring the absorption of energy is :
1.
2.
3.
4.
Consider the following statements:
(I) Rutherford name was associated with the development of periodic table.
(II) A metal M having electronic configuration is d-block element.
(III) Diamond is an element.
(IV) The electronic configuration of the most electronegative elements is
and select the correct one from the given codes.
(A) I, II, IV (B) I, II, III, IV
(C) II, IV (D) I, III, IV
There are four elements 'p', 'q', 'r' and 's' having atomic number Z-1, Z, Z+1 and Z+2 respectively. If there element 'q' is an inert gas, select the correct answers from the following statements.
(i) 'p' has most negative electron gain enthalpy in the respective period.
(ii) 'r' is an alkali metal.
(iii) 's' exists in +2 oxidation state.
(1) (i) and (ii)
(2) (ii) and (iii)
(3) (i) and (iii)
(4) (i), (ii) and (iii)
Given below are four orders for the size of the species. Choose the correct ones:
(a)
(b)
(c)
(d)
1. (a), (b) & (c)
2. (b), (c) & (d)
3. (a), (c)
4. (a), (b), (c) & (d)
Which of the following orders are correct for the ionization energies?
(A) \( B a < S r < C a \)
(B) \(S^{2 -} < S < S^{2 +}\)
(C) \(C < O < N\)
(D) \(M g < A l < S i\)
1. A, B and D
2. A, C and D
3. A, B and C
4. A, B, C and D
The electron gain enthalpies of halogens in kJ mol-1 are given below.
F =-332, Cl =-349, Br =-325, I =-295.
The lesser negative value for F as compared to that of Cl is due to:
1. Strong electron-electron repulsions in the compact 2p-subshell of F.
2. Weak electron-electron repulsions in the bigger 3p-subshell of Cl.
3. Smaller electronegativity value of F than Cl.
4. 1 & 2 both
Which of the following statements are correct ?
(i) | Generally the radius trend and the ionization energy trend across a period are exact opposites. |
(ii) | Electron affinity values of elements may be exothermic (negative) or endothermic (positive). |
(iii) | The first ionization energy of sulphur is higher than that of phosphorus. |
(iv) | \(Te^{2-} > I^- > Cs^+ > Ba^{2+}\) represents the correct decreasing order of ionic radii. |
1. (i), (iii) and (iv)
2. (ii), (iii) and (iv)
3. (i), (ii) and (iv)
4. (i), (ii) and (iii)
Which of the following statements is not correct?
(1) The first ionization energies (in KJ ) of carbon, silicon, germanium, tin, and lead are 1086, 786, 761, 708 and 715 respectively.
(2) Down the group, electronegativity decreases from B to Tl in boron family.
(3) Among oxides of the elements of carbon family, CO is neutral, GeO is acidic and SnO is amphoteric.
(4) The 4f- and 5f- inner transition elements are placed separately at the bottom of the periodic table to maintain its structure.