In Chemistry, to better determine the position of a certain electron, quantum numbers are used. The four quantum numbers are n, l, m and s. In the given above of n= 4, the principal quantum number is 4 and this represents the overall relative energy in the orbital. This means that we are to find the maximum number of electrons in fourth main energy level and the answer is 32.

Thus 174 protons would make at most 6 copper atoms. However, it would take 174 extra electrons (29 per atom) and even more neutrons than that to construct neutral copper atoms with stable nuclei.
Answer:
1.3×10²³ formula unit
Explanation:
Given data:
Mass of CaCl₂ = 23.8 g
Number of formula unit = ?
Solution:
Number of moles = mass/molar mass
Number of moles = 23.8 g/110.98 g/mol
Number of moles = 0.21 mol
1 mole of any substance contain 6.022×10²³ formula unit
0.21 mol × 6.022×10²³ formula unit / 1mol
1.3×10²³ formula unit