Arrange of the following in :
Increasing order of basic character
MgO, SrO, K₂O, NiO, Cs₂O

Arrange of the following in :
Arrange the following ions in order of their increasing radii:
Li⁺, Mg²⁺, K⁺, Al³⁺

The linear structure is assumed by

Arrange the following :

Increasing strength of hydrogen bonding (X-H-X):

O, S, F, Cl, N