Behind the Bohr Diagram

BEHIND THE BOHR DIAGRAM : 

BEHIND THE BOHR DIAGRAM 1 M.BREGAR (DANTE C.S.S.)

Line Spectra : 

Line Spectra Phenomena which allowed Neil Bohr to develop his “Planetary Model” of the bohr diagram Key Idea When matter is heated, it produces light Think a lightbulb Lightbulb is heated to 2200◦C 2 M.BREGAR (DANTE C.S.S.)

A lightbulb? : 

A lightbulb? FILAMENT 3 M.BREGAR (DANTE C.S.S.)

Slide 4: 

Passing sunlight through a prism breaks the light down into a spectrum of colours Light Spectra 4 M.BREGAR (DANTE C.S.S.)

Light Spectra : 

Light Spectra When exposed to light/electricity pure elements give out a light 5 M.BREGAR (DANTE C.S.S.)

Light Spectra : 

Light Spectra Many elements will emit a specific colour, most generally emit red light ARGON GAS Emits high energy blue light NEON GAS Emits low energy red light KRYPTON GAS Emits mid energy yellow light 6 M.BREGAR (DANTE C.S.S.)

Slide 7: 

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Light Spectra : 

Light Spectra If you pass this “light” through a prism, every single element has its UNIQUE SPECTRUM 8 M.BREGAR (DANTE C.S.S.)

Light Spectra : 

Light Spectra 9 M.BREGAR (DANTE C.S.S.)

Slide 10: 

SODIUM MERCURY LITHIUM HYDROGEN 10 M.BREGAR (DANTE C.S.S.)

Light Spectra : 

Light Spectra 11 M.BREGAR (DANTE C.S.S.)

Light Spectra : 

Light Spectra 12 M.BREGAR (DANTE C.S.S.)

So What’s Happening? : 

So What’s Happening? Bohr had two key questions: Why does matter emit light when heated? Why is the light spectra unique for each element? 13 M.BREGAR (DANTE C.S.S.)

Planetary Model of the Atom : 

Planetary Model of the Atom Orbits Electrons are found in areas around the nucleus called orbits Each orbit is an “energy level” Orbits further from the nucleus INCREASE IN ENERGY 14 M.BREGAR (DANTE C.S.S.)

Slide 15: 

Atoms can exist in two states the ground state or an excited state GROUND STATE Normal “low energy” state of atoms Electrons are in lower energy orbits EXCITED STATE ENERGY Electrons jump to higher energy orbits Atoms can not remain in this “excited state” 15 M.BREGAR (DANTE C.S.S.)

Slide 16: 

But why is light released? GROUND STATE EXCITED ATOM Atom currently in excited state Electrons can not remain in excited state Normal state of atoms, electrons at lower energy level Electrons can not remain at higher energy orbits They fall back to their “ground orbits” but this releases light ! 16 M.BREGAR (DANTE C.S.S.)

A lightbulb? : 

A lightbulb? FILAMENT 17 M.BREGAR (DANTE C.S.S.)

But why do atoms have a unique light spectra? : 

SODIUM SODIUM LITHIUM But why do atoms have a unique light spectra? 18 M.BREGAR (DANTE C.S.S.)

But why do atoms have a unique light spectra? : 

But why do atoms have a unique light spectra? The collection of narrow bands of light energy is referred to as an emission line spectrum, and the individual bands of light are called spectral lines. 19 M.BREGAR (DANTE C.S.S.)

Slide 20: 

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Slide 21: 

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Planetary Model of the Atom : 

Planetary Model of the Atom Electrons in an atom move in circular paths called orbits found outside of the nucleus of the atom 22 M.BREGAR (DANTE C.S.S.)

Planetary Model of the Atom : 

Planetary Model of the Atom Each electron in an orbit, carries a specific amount of energy The farther away the electron is from the nucleus, the more energy it has 23 M.BREGAR (DANTE C.S.S.)

Planetary Model of the Atom : 

Planetary Model of the Atom The order of filling electrons in the first three orbits is 2,8,8 Electrons are more stable at lower energy levels closer to the nucleus 24 M.BREGAR (DANTE C.S.S.)