Answer
alkali metals
Explanation:
metals of first and second group of periodic table have ability to donate electron and form positive ions
No reaction will occur because magnesium is more reactive than zinc. If you did the reverse ( magnesium particles in zinc sulphate solution) than a reaction will occur in which the zinc will be displaced from solution.
Answer is a because it has the potential to go down but it hasn’t went down yet!!!!!!
The percent of O in Cr₂O₃ : 31.58%
<h3>Further explanation</h3>
Given
Cr = 52.00 amu, O = 16.00 amu
Required
The percent of O
Solution
MW Cr₂O₃ = 2 x Ar Cr + 3 x Ar O
MW Cr₂O₃ = 2.52+3.16
MW Cr₂O₃ =152 amu

Simple. The atomic number is the number of protons (12) and the mass number is the number of neutrons and protons combined. So you'd subtract 12 from 25 (25-12=) and that'd get you 13 as your answer. If you need to find the number of electrons, it'll be the same as the number of protons unless it has a certain charge and if it does, if it's positive it has more protons (+) than electrons (-), if it is negative it has more electrons (- negatively charged) than protons (+ positively charged)