Calculate the number of moles of oxygen atoms in 35.2 grams of oxygen.

 Atomic Weight of Oxygen is 16 g/mol 

Use the equation n=m/MM

You know m (mass) and MM (molar mass), sub in into the equation.

Ans: 2.2 mol

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.