`[SiF_6]^(2-)` exist but `[Sicl_6]^(2-)` does not Explain.

3f orbital does not exist-explain.

He_2 molecule does not exist Explain.

CIF_3 exists but FCI_3 does not why?

Why does R_3P=0 exist but R_3N=0 does not?

SF_6 is used as a gaseous electrical insulator. Explain.

Give reasons: [Ti(H_2O)_6]^(3+) is coloured while [Sc(H_2O)_6]^(3+) is colourless.

SF_6 is used as a gaseous electrical isulator, explain.

What will be the correct order for the wave lengths of absorption in the visible region for the following. Explain the fact. [Ni(NO_2)_6]^+, [Ni(H_2O)_6]^(2+)

in what ratio does the point P(2,5) divide the line joining the points A(-8,9) and B(-6,9).