Let\'s build a helium atom. Start with a nucleus of 2 protons and 2 neutrons (an
ID: 1525936 • Letter: L
Question
Let's build a helium atom. Start with a nucleus of 2 protons and 2 neutrons (and a charge of +2e). Then bring in an electron from infinity to the mean radius of an electron in the helium atom, r_H = 3.1 times 10^-11 m. Then bring in a second electron to the same distance on the other side. Calculate the energy gained by the system constructing this atom. Remember that the first particle you bring in (the nucleus) has no energy change, since there are no other particles for it to interact with. The first electron interacts with the nucleus, while the second electron is both attracted to the nucleus, and repelled by the other electron (which is 2r_H, from it). Element = 1.60 times 10^-19.Explanation / Answer
charge on nucleus = +2e
charge on electron = e
PE for nucleus and 1 electron system
EPE = k (q1)(q2)/ d
= k (2e)(e) / rH
e = 1.602 x 10^-19 C and rH = 3.1 x 10^-11 m
= - 1.486 x 10^-17 J
between two electrons :
PE = k (e^2) / 2rH
= 3.716 x 10^-18 J
energy gain = 1.486 x 10^-17 - 3.716 x 10^-18
= 1.115 x 10^-17 J .....Ans
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.