I NEED THIS FOR A TEST, FAST!
 The element phosporus is located to the right of the element magnesium along the same period in the periodic table.
Which best describes the relationship of the elements?
Magnesium has a larger atomic number. 
Phosphorus has a larger atomic mass.
Magnesium is in the same category as phosphorus. 
Phosphorus has similar chemical properties as magnesium.
Which best describes the relationship of the elements?