6 Atoms!
Mg = 1 atom.
O = 4 atoms.
A = 1 atom.
Answer:
5.41 ×10⁻²²
Explanation:
We were told right from the question that both the Zinc ions and the Zinc oxide adopts a face-centered cubic arrangement.
Then, the number of ZnO molecule in one unit cell = 4
The standard molar mass of ZnO = 81.38g
Avogadro's constant = 6.023 × 10²³ mole
∴
The mass of one unit cell of zinc oxide can be calculated as:
= 
= 5.40461564×10⁻²²
≅ 5.41 ×10⁻²²
∴ The mass of one unit cell of zinc oxide = 5.41 ×10⁻²²
The noble gases don't react because they have their full orbital. They have 8 valence electrons, meaning that they are happy and stable. They dont need any more electrons, which means that they dont need to bond. That makes them un- reactive.
Answer:
m = 671 grams
Explanation:
Given that,
No of moles, n = 4.9
Molar mass of Barium, M = 137 g
Mass divided by molar mass is equal to no of moles. It can be given by the formula as follows :

or
m = 671 grams
So, the total mass of the sample of Barium is 671 grams.