Magnesium is a medication used as a mineral supplement used to prevent and treat low levels of minerals in the blood. When magnesium (Mg) reacts with oxygen (O2 ) it forms magnesium oxide (MgO) __2_Mg + ___ O2 __2_ MgO

If 25g of Mg reacts with O2, and 100 g of MgO is formed, how much O2 was needed?

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."