the equation of energy level

[George_Zhu]

Can anyone talk about why the En=-hr/n2 has negative sign here again?

[Jeril Joseph 1B]

There is a negative sign present since you're decreasing energy levels to help excite an electron to be released. The electron is losing energy, so you wouldn't have a positive energy amount calculated if the electron energy is being lost. However, it's important to note that the equation mentioned only applies to the Hydrogen spectrum.

[Leah farhadi 1F]

There is a negative sign present, because it signifies that there is a loss of energy. Since we are taking 0 as our reference point, when electron is completely removed and not interacting with the nucleus, the negative sign signifies the idea that a bound electron has a lower energy level than a free electron.

[George_Zhu]

There is a negative sign present since you're decreasing energy levels to help excite an electron to be released. The electron is losing energy, so you wouldn't have a positive energy amount calculated if the electron energy is being lost. However, it's important to note that the equation mentioned only applies to the Hydrogen spectrum.

but why it will decrease energy level to excite a electron?

[Chem_Mod]

If the electron is excited it will go to a higher energy level, which requires the input of energy thus maintaining the law of conservation of energy. When the electron decreases in energy and goes to a lower energy level, then to maintain the conservation of energy the electron falling in energy also releases energy, which can be in the form of light.