In borax the number of B-O-B links and B-OH bonds present are, respectively
five and four
four and five
three and four
five and five
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
If the first ionization energy of H atom is 13.6 eV, then the second ionization energy of He atom is
27.2 eV
40.8 eV
54.4 eV
108.8 eV
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