Which of the following molecular species has unpaired electrons(s)?
Răspuns
(C)
$$O_2^-$$
2
Identify the least stable ion amongst the following
Răspuns
(B)
Be-
3
Specify the coordination geometry around and hybridisation of N and B atoms in a 1 : 1 complex of BF3 and NH3
Răspuns
(A)
N : tetrahedral, sp3; B : tetrahedral, sp3
4
Identify the correct order of acidic strengths of CO2, CuO, CaO, H2O
Răspuns
(A)
CaO < CuO < H2O < CO2
5
If the nitrogen atom has electronic configuration 1s7, it would have energy lower than that of the normal ground state configuration 1s22s22p3, because the electrons would be closer to the nucleus. Yet 1s7 is not observed because it violates
Răspuns
(C)
Pauli exclusion principle
6
Rutherford's experiment, which established the nuclear model of the atom, used a beam of
Răspuns
(D)
helium nuclei, which impinged on a metal foil and got scattered
