Setting of plaster of Paris is
dehydration
oxidation with atmospheric oxygen
combination with atmospheric CO2
hydration to yield another hydrate
The set representing the right order of ionic radius is
Li+ > Na+> Mg2+ > Be2+
Mg2+ > Be2+> Li+> Na+
Na+> Mg2+> Li+> Be+
Na+> Li+> Mg2+> Be+
The element that forms stable compounds in low oxidation state is
Mg
Al
Ga
Tl
D.
Tl
Thallium (Tl), due to inert pair effect shows stable lower oxidation state and forms stable compounds in low oxidation state.
Atomic radius (pm) of Al, Si,N and F respectively is:
117, 143, 64, 74
143, 117, 74, 64
143, 47, 64, 74
64, 74, 117, 143
The correct order of hydration enthalpies of alkali metal ions is:
Li+ > Na+ > K+ > Cs+ > Rb+
Na+ > Li+ > K+ > Rb+ > Cs+
Na+ > Li+ > K+ > Cs+ > Rb+
Li+ > Na+ > K+ > Rb+ > Cs+
The isoelectronic set of ions is :
Li+, Na+, O2- and F-
N3-, O2-, F- and Na+
F-, Li+, Na+ and Mg2+
N3-,Li+, Mg2+ and O2-