Question

The line emission spectra for different gases vary. Why is this and what can it be used for ... "check all that apply"

the excited atoms of that gas emit all wavelenghts of light producing a unique spectrum

Actually they are all the same

the excited atoms of that gas emit only certain wavelengths of light producing a unique spectrum

the excited atoms of that gas emit only one wavelength of light producing only one line associated with each gas.

Excited gaseous atoms produce characteristic spectra that can be used to identify the element.

Answer 1

these two options are correct

the excited atoms of that gas emit only certain wavelengths of light producing a unique spectrum

Excited gaseous atoms produce characteristic spectra that can be used to identify the element.

Reason:

Gases atoms on absorbing radiation excite its electrons from the ground state to the higher levels and while coming back it reemits the absorbed light, the energy difference between the two levels determines its wavelength. `This will be only certain wavelengths of light producing a unique spectrum that can be used to identify the element.