 What are the components of an atom?  What is in the nucleus?  What are the charges of the subatomic particles?  Where are the electrons?

Planets around the sun Could only explain simple properties of atoms Red fire vs blue fire

Each electron is on an orbit that has a fixed energy. These orbits are called energy levels. Orbit = energy level No “in between” levels (ladder example) A quantum is the amount of energy needed to move from one level to the next.

 aka Quantum Mechanical Model  There is no specific path electrons take  Demonstrates the probability of finding an electron in that location.  No more orbits. We now have energy levels.

 A region of space where there is a high probability of finding an e- (~90%)  Each energy level has orbit als. These are not orbits. Bad choice of name.

 Each atom is categorized by the number of levels and sublevels.  The number of levels are referred to as n.  Also, the number of sublevels equals n.  So….  energy level 1 has 1 sublevel,  energy level 2 has 2 sublevels, etc…..

 There are 4 types or orbitals and we will only focus on 3 (s orbitals, p orbitals, and d orbitals)  The number of sublevels = n 2 where n =the energy level  Each orbital has a different shape and they all build on one another.  Each orbital can only hold 2 e- so the number of electrons at each energy level = 2 n 2.

Energy level (n)# of sublevels (n)Sublevels (n 2 )# of e- that n can hold (2n 2 ) 111 (1 s orbital)2 224 (1 s orbital and 3 p orbitals)8 339 (1 s orbital, 3 p orbitals, and 5 d orbitals) (1 s orbital, 3 p orbitals, and 5 d orbitals, and 7 f orbitals). 32

 Sphere shaped  Hold 2e- Cross section

 Dumbbell shaped  Hold 2e- each for a total of 6 This is 1 p orbital, not 2

Hold 2e- each for a total of 10.

Energy level (n)# of sublevels (n)Sublevels (n 2 )# of e- that n can hold (2n 2 ) 111 (1 s orbital)2 224 (1 s orbital and 3 p orbitals)8 339 (1 s orbital, 3 p orbitals, and 5 d orbitals) (1 s orbital, 3 p orbitals, and 5 d orbitals, and 7 f orbitals). 32

 Rule #1 – electrons occupy lowest energy level first.  S sublevel is always the lowest…….ALWAYS

 Rule # 2 – an orbital may only hold 2 electrons with opposite spins.

 Rule #2 - Every orbital in a sublevel is singly occupied before any orbital is doubly occupied

 Write the electron configuration for a phosphorus atom.  First, how many electrons need “homes?”  Next, place electrons in the orbital with the lowest energy level.  Continue adding electrons in orbitals with the next higher energy.  1s 2 2s 2 2p 6 3s 2 3p 3 ____ ____ ____ ____ ____ _____ ____ _____ ____ 1s 2s 2p 2p 2p 3s 3p 3p 3p

 Ground state  Lowest possible energy  Excited state  Absorption of energy by electron  Electron moves to the next energy level.  Light is emitted when it moves back to it’s ground state.  This transition from the excited back to ground state produces both a distinctive visible color and emission spectrum. “Spectral fingerprints.”

H He Ne Na Hg C N Mg

 Wavelength – distance between crests

 Frequency – number of wave cycles in a given time

 Amplitude – height of wave from zero to crest

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