Srujana and Sahana are best friends and studying class VIII their science teacher has given a task to predict the nature of oxides of different elements like metals and non metals. They have conducted some experiments and reported their observations.

Sample	Physical appearance before reaction	Physical appearance after reaction (Burning)	Effect on litmus
Magnesium	Slivery grey	White ash	Red to blue
Sulphur	Yellow	Suffocating gas	Blue to red

Then the nature of oxides of Mg and S respectively is