Which of the following molecular species has unpaired electrons(s)?
答え
(C)
$$O_2^-$$
2
Identify the least stable ion amongst the following
答え
(B)
Be-
3
Specify the coordination geometry around and hybridisation of N and B atoms in a 1 : 1 complex of BF3 and NH3
答え
(A)
N : tetrahedral, sp3; B : tetrahedral, sp3
4
Identify the correct order of acidic strengths of CO2, CuO, CaO, H2O
答え
(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
答え
(C)
Pauli exclusion principle
6
Rutherford's experiment, which established the nuclear model of the atom, used a beam of
答え
(D)
helium nuclei, which impinged on a metal foil and got scattered
