The stable bivalency of Pb and trivalency of Bi is
due to d contraction in Pb and Bi
due to relativistic contraction of the 6s orbitals of Pb and Bi, leading to inert pair effect
due to screening effec
due to attainment of noble liquid configuration
Which of the following is correct?
Radius of Ca2+ <Cl- < S2-
Radius of <Cl- < S2- < Ca2+
Radius of S2-= Cl-= Ca2+
Radius of Ca2+ >Cl- > S2-
Which one of the following has the lowest ionisation energy?
1s2, 2s2, 2p6
1s2, 2s2, 2p6, 3s1
1s2, 2s2, 2p5
1s2, 2s2, 2p3
An oxide of a non-metal has the following properties
(i) It acts both as proton donor as well as proton acceptor
(ii) It reacts readily with basic and acidic oxides
(iii) It oxidies Fe at its boiling point. The oxide maybe
P2O5
SiO2
H2O
CO2
Consider the following changes
M(s) → M(g) ... (1)
M(g) → M2+(g) + 2e- ...(2)
Mg) → M+(g) + e- ...(3)
M(g) → M2+(g) + e- ...(4)
M(g) → M2+ (g) + 2e- ...(5)
The second ionisation energy of M could be determined from the energy values associated with
1 + 2 + 4
2 + 3 - 4
1 + 5 - 3
5 - 3
If the ionisation energy and electron affinity of an element are 275 and 86 kcal mol-1 respectively, then the electronegativity of the element on the Mulliken scale is
2.8
0.0
4.0
2.6
Among the elements Ca, Mg, P and Cl, the order of increasing atomic radii is
Mg< Ca< Cl< P
Cl <P <Mg< Ca
P <Cl< Ca< Mg
Ca <Mg <P < Cl
B.
Cl <P <Mg< Ca
With increase in the number of electrons in the same shell, the atomic radii decreases due to increase in effective nuclear charge. However, atomic radii increases, as the number of shells increases. Thus, on moving down a group atomic radii increases. The electronic configuration of the given element is
Mg12 = [Ne] 3s2
Ca20 = [Ar]4s2
P15 = [Ne] 3s2 3p2
Cl17 = [Ne]3s2 3p5
In Mg, P and Cl, the number of electrons are increasing in the same shell, thus the order of their atomic radii is
Cl <P < Mg
In Ca, the electron is entering in higher shell, thus, it has the highest atomic radii among the given. Thus, the order of radii is
Cl<P <Mg< Ca