Answer:
electrons are fermions, they can only access an energy level if it has not already been occupied by another electron. Thanks to this principle, there is a minimum energy level within the atom and it is not possible for an electron to collapse to the nucleus because it cannot exceed this} threshold.
Explanation:
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Solution
Given mass of FeBr2 = 85.5 g
Molar mass of FeBr2 = 215.65
No. of Moles of FeBr2 = Given Mass / Molar mass = 85.5 / 215.65
No. of Moles = 0.3964
Given Volume is 450 mL i.e. 0.450 L
Now Concentration = 0.3964/0.450
Hence Concentration = 0.881 mol/L
Answer: Arsenic has five valence electrons.
Explanation: Good luck!