1. Modern Atomic Model and EMR

2. Understand how line spectra are created.
Describe the electromagnetic spectrum in terms of frequency, wavelength, and energy.
Understand how line spectra are created.
Additional KEY Terms
Spectroscopy Emission Quantum
Line spectrum

3. Composed of radiated waves of both electrical and magnetic energy
Maxwell (1860) - all energy radiated from objects (including visible light) is electromagnetic radiation.
Composed of radiated waves of both electrical and magnetic energy

4. Amplitude: height of the wave from origin to crest.
Wavelength (λ - “lambda”): distance from point to the same point on the next wave.
Frequency (ν – “nu” or ƒ): number of wavelengths, or cycles, that pass a point per unit time.
Frequency measured in cycles per second (s-1), or the SI unit hertz (Hz)
Amplitude: height of the wave from origin to crest.
Wavelength and frequency do not affect amplitude
Wavelength and frequency are inversely related

5. Types of Electromagnetic radiation
f and λ determine what you see or feel, amplitude determines how bright or hot

6. c = λƒ c = λν All EMR radiates at 3.00 x 108 m/s in a vacuum.
This universal value (c) is a product of the wavelength and frequency of the radiated energy.
“speed of light”
c = λƒ
c = λν

7. It will always be - ROY G BIV
Sunlight (white light) shone through a prism separates it into a continuous spectrum of colours.
The different wavelength for each colour causes them to refract or bend at different angles
It will always be - ROY G BIV

8. Investigated heated objects and
Planck (1900)
Investigated heated objects and
Burning small amounts of each element gave off a unique colour of light
Used to detect a metals presence
Colour
Element
green
copper
yellow
sodium
red
strontium
yellow-green
barium
orange-red
calcium
purple
potassium
purple-red
lithium
Focusing this light through a prism also produces a spectrum, but ONLY distinct lines appear

9. Disclaimer: This is not as simple as my drawing looks
Energy emitted by a element can be separated – to produce a Line spectrum
(emission spectrum)
Disclaimer: This is not as simple as my drawing looks

10. The colored lines of the atoms (or Spectral Lines) are a kind of "signature" for the atoms.
Spectroscopy and spectrophotometry are techniques used to investigated EMR emissions. C O

11. Quantum is the smallest “packet” of energy gained or lost by an atom.
Planck's radiation law:
Equation that accounted for light from heated objects, BUT it needed energy to be gained or lost in discrete amounts – called quanta.
Quantum is the smallest “packet” of energy gained or lost by an atom.
Planck couldn’t explain WHY energy had to be “quantized,” but it worked and predicted experimental values

12. So higher frequency waves contained larger “packets” of energy
Energy contained in a quantum was directly related to the frequency of radiation emitted.
Eq = hf
E – energy of a quantum (Joules)
h – Plank’s constant (6.626 x J s)
f – frequency of absorbed or emitted EMR
So higher frequency waves contained larger “packets” of energy

13. Understand how line spectra are created.
CAN YOU / HAVE YOU?
Describe the electromagnetic spectrum in terms of frequency, wavelength, and energy.
Understand how line spectra are created.
Additional KEY Terms
Spectroscopy Emission Quantum
Line spectrum