## When do you use a negative sign in the Bohr equation?

H-Atom ($E_{n}=-\frac{hR}{n^{2}}$)

Darren Nguyen 1F
Posts: 60
Joined: Sat Sep 14, 2019 12:15 am

### When do you use a negative sign in the Bohr equation?

Sometimes it's there, sometimes it isn't

Kim Chen
Posts: 13
Joined: Thu Oct 10, 2019 12:15 am

### Re: When do you use a negative sign in the Bohr equation?

I believe the negative sign is always there. The negative sign is there because of the frame of reference -- when E=0, the electron is free. As the electrons go down in orbitals, they lose energy.

Mansi_1D
Posts: 50
Joined: Fri Aug 02, 2019 12:15 am

### Re: When do you use a negative sign in the Bohr equation?

It's negative when the electron is going from higher energy level (initial) to a lower energy level (final) which would make sense because energy is released when electron move from a higher energy level to a lower energy level. In the equation, you would subtract final - initial which would give you a negative value if this was the case.

charleejohnson1L
Posts: 60
Joined: Fri Aug 30, 2019 12:17 am

### Re: When do you use a negative sign in the Bohr equation?

The negative sign is always present in the equation! :) Sometimes people don't use it when calculating because it makes sense that the final answer would end up being negative in any case. Hope this helps!

Posts: 82
Joined: Wed Sep 18, 2019 12:21 am

### Re: When do you use a negative sign in the Bohr equation?

The negative sign in the Bohr equation is there because it represents the energy the electron must overcome so when the electron and neutron are completely separated, the energy will equal 0.

Kyla Grunden 1L
Posts: 46
Joined: Sat Sep 07, 2019 12:16 am

### Re: When do you use a negative sign in the Bohr equation?

Hello, I believe there is always a negative sign in Bohr's equation. I looked it up and a previous user on this site said "The negative sign in Bohr's equation is there because E=0 when the electron and neutron are separated completely (when the electron is free). So, as they get closer (or get lower in orbitals), they are losing energy and therefore the energy calculated when doing Bohr's equation is negative".

Hope this helps!

Camille 4I
Posts: 57
Joined: Sat Aug 24, 2019 12:18 am

### Re: When do you use a negative sign in the Bohr equation?

I'm pretty sure that as energy can't be "negative", you should take the absolute value of the answer that you get at the end of the equation.

Zoya Mulji 1K
Posts: 81
Joined: Thu Jul 11, 2019 12:15 am

### Re: When do you use a negative sign in the Bohr equation?

the negative is always there in the equation because if we say that as n --> infinity, that E is 0, as the electron comes back down from high energy levels and approaches the nucleus, it loses energy and the values for energy are "negative."
in a review session, a good analogy used was ... consider energy as money and technically you can't have "-" money, but when you lose it, you represent the values as negative.