When two identical ions are separated by a distance of 4.2×10−10 m , the electrostatic force each exerts on the other is 5.2×10−9 N .

Question

How many electrons are missing from each ion?

Answer 1

F = kq² / r²

 

q = ne

 

F = k(ne)² / r²

 

n = √(r²F / ke²) = (r/e) √(F/k)

 

k = 9 x 10⁹ Nm²/C²

 

e = 1.6 x 10^-19 C

 

n = [(4.2 x 10^-10) / (1.6 x 10^-19)] √[(5.2 x 10^-9) / (9 x 10⁹)] ≅ 1.995 ≅ 2

 

2 electrons are missing from each atom.