To find the amount of atoms in a mole you will use Avragadro's constant. So 2.8 x 6.02 x 10^23 (2.8x 6.02 ten to the power of 23)
2.8x 6.02 10^23
Symbiosis describes close<span> interactions between two or more different species. There are four main types of symbiotic relationships: mutualism, commensalism, parasitism and competition.</span>
The compound formed will be X2Y3 with oxidation number of X = +3 and of Y = -2.
Example of X2Y3 type compounds are Fe2O3 and Mn2O3.
Hope this helps!!