emission and absorption spectra

What is absorption spectra?

• Rainbow with black lines

What do each black lines in an absorption spectra mean?

Amount of energy absorbed by atom when electrons promoted from low energy levels to higher energy level.

What is an emission spectra?

Coloured lines on black background through a spectrometer.

How does emission spectra work?

• if energy source removed eg. Heat

• Electrons will relax to lower energy level (ground state)

• And emit the photon of energy they absorbed.

What is the atomic emission spectrum of hydrogen?

• simplest emission spectrum (energy released)

What happens when lines on the hydrogen spectrum get closer?

Energy decreases.

what happens when an electron gets from an excited state to ground state?

• energy given out

• More energy = higher frequency

What is the Lyman series?

• electrons fall to n=1

• In Ultra violet area

What is the Balmer series?

• electrons fall to n = 2

• In visible area

What is Paschen series?

• electrons fall to n= 3

• In infa-red area

Why can’t we see any hydrogen electron transition from n= 1 ( ground state)

Because it is lowest possible energy level.

What is the convergence limit?

Spectral lines become too close together that they have continuous band of radiation and separate lines cannot be distinguished

What is the relationship between frequency and energy?

• directly proportional

• If energy increases so does frequency

What is the relationship between frequency and wavelength?

• inversely proportional

• If frequency increases, wavelength decreases

How is the frequency, energy and wavelength from radio —> gamma rays

• increasing frequency & energy

• Decreasing wavelength

Equation of energy?

Energy = h (Planck’s constant) x frequency

Speed of light constant equation?

c (speed of light constant) = wavelength (m) x frequency

How to calculate ionisation energy of hydrogen atom?

• Find energy x Avagardos constant (data sheet)