Identify the metalloid in period 3 with more protons than sodium (Na) and fewer valence electrons that chlorine (Cl). *

Arsenic (As)
Germanium (Ge)
Magnesium (Mg)
Silicon (Si)

Does anyone know a lot about how to: - calculate mass of magnesium metal - calculate the actual yield of magnesium oxide - calculate the theoretical yield of mgo - calculate the percent yield of mgo - determine the percent yield of mgo - determine the average percent yield of mgo i had to do an online lab and its asking these questions but i have no idea where to start or how to be able to find these things. i can post the chart of the data from the lab or if you can tell me exactly how i can find each.

What are the first three quantum numbers for the electrons located in subshell 2s?

How have the greenhouse gasses increased from the year 2000 to 2018