Answer:
4
Explanation:
It should be 4
The mass is 9
There are 5 neutrons
There are 9 - 5 = 4 protons
So it is the 4th element on the periodic table.
Y2O3 is the molecular formula. Yttrium (III) oxide is also called yttria. It is a white substance and is air-stable. The usual application for this compound is a starting material for inorganic compounds and in material science. IT is insoluble in water and has a high melting point.
Answer:
lithium oxide is soluble in water