Electrons and Light Unit 4 A Electron Configuration

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Electrons and Light! Unit 4 A

Electrons and Light! Unit 4 A

Electron Configuration Review! p Write the Noble Gas Configurations for these elements! n n

Electron Configuration Review! p Write the Noble Gas Configurations for these elements! n n n Fe Rb Cl

Noble Gas Configurations & Valence Electrons p Fe – [Ar]4 s 23 d 6

Noble Gas Configurations & Valence Electrons p Fe – [Ar]4 s 23 d 6 p Rb – [Kr]5 s 1 p Cl – [Ne]3 s 23 p 5 p Valence e- - electrons in the highest orbital or energy level.

Valence Electrons p Fe – [Ar]4 s 23 d 6 {2 valence e-} p

Valence Electrons p Fe – [Ar]4 s 23 d 6 {2 valence e-} p Rb – [Kr]5 s 1 {1 valence e-} p Cl – [Ne]3 s 23 p 5 {7 valence e-} p These are the electrons that are involved in bonding and chemical reactions!!!!!!!

Valence Electrons and the Periodic Table

Valence Electrons and the Periodic Table

What do e- have to do with light? p When you add energy to

What do e- have to do with light? p When you add energy to an element (perhaps by heating it up), the valence eget “excited”. In other words they jump up to a higher energy level or orbital. p BUT… they are unstable up there. So they release that added energy in the form of colored light! p Huh?

So what exactly is light? p Light is a wave of energy, a small

So what exactly is light? p Light is a wave of energy, a small part of the electromagnetic spectrum!

Light as a Wave p p Light moves in wave from the light source

Light as a Wave p p Light moves in wave from the light source to you eye or other detector! Waves have several characteristics!

Wave Characteristics c = λ× ν c = speed of light = 3. 00

Wave Characteristics c = λ× ν c = speed of light = 3. 00 × 108 m/s λ = wavlength ν = frequency

Light can also act as particles, we call them PHOTONS!!!!!! p Moving along those

Light can also act as particles, we call them PHOTONS!!!!!! p Moving along those waves, there are little packets of energy called photons. n Photons have specific amounts of energy as determined by the frequency of the light. n. E =h×ν n. E = hc λ n The higher the frequency of the light, the more energy the light has.

So how does light tie into excited electrons? p When you add energy to

So how does light tie into excited electrons? p When you add energy to an element, it’s valence e- absorb that packet of energy & become unstable. In order to return to stability (lower their energy) they “spit out” that energy in the form of a photon that has a frequency in the visible light part of the electromagnetic spectrum that we can see.