Chemistry ch 5
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Properties are determined by
electrons

That particles of matter have the same properties of waves & vice versa
deBroglie

deBroglie's equation
 E=mc2 (einstein) E=hv (Planck) c=yv / v=c/y
 hv=mc2, so hc/y=mc2, so y=hc/mc2, c's cancel and y=h/mc

Waveparticle duality
A stream of electrons acts the same as waves of light

How was waveparticle duality proved
mathematically by deBroglie's equations

C=3x10^8 in a VACUUM. But, how does it travel elsewhere?
It travels at different speeds and changes directions (refracts)

Index of refraction
 specific to a substance
 Calculated by the bending of a light ray passing from a vacuum into a new substance.

Momentum
 P
 mass x velocity
 Tells where an object is going
 Since y = h/mv, y = h/p

As the momentum of an object increases,
y decreases

As the momentum of an object decreases,
y increases.

To see an object,
It must be hit by a photon of light & reflected to our eyes.

Uncertainty Principle
you can't ever know the exact position and momentum of a moving object at any given instant.

You can't ever see the exact position of an electron because
The photon is deflected, but the electron is so small that it causes the electron to move.

Uncertainty Principle by
Heisenerg

Who treated the electron as a particle?
Schrodinger

Theory of Quantum Mechanics
 Schrodinger
 Studies the behavior of very small objects travelling at velocities at or near the speed of light

Newtonian Mechanics
 Newton
 studies the behavior of VISIBLE objects travelling at ORDINARY velocities.

Who proved the planetary theory wrong?
Schrodinger

Orbitals
3dimensional regions around the nucleus that give the probable location of the electron

Quantum Numbers tell us
 The most likely position of the electron in an electron cloud
 Specific properties of the orbitals
 Properties of the electrons in the orbitals

Primary Quantum Number
 n
 MAIN ENERGY LEVEL occupied by the electron
 values from 17, 1 is the smallest and closest to the nucleus
 as n increases, the energy of the electron it contains increases, as doesthe distance from the nucleus.
 2xn^2 = maximum number of electrons an energy level can hold.

Second Quantum Number
 cursive l/ribbon
 SUBLEVEL and SHAPE of the orbital
 Number of sublevels in an energy level = n
 Except in n=1, sublevels of different shapes exist in the same energy level

Third Quantum Number (m)
ORBITALS and SPATIAL ORIENTATION of the orbitals in a sublevel

n^2
number of orbitals in an atom










Electron configurations are in what state?
ground

Outermost energy level
atoms with full s and p levels (8e)


Rules for filling energy levels with electrons
 1. Aufbau Principle
 2. Pauli Exclusion Principle
 3. Hund's Rule
 4. Diagonal Rule

Aufbau Principle
electrons occupy the lowest energy orbital that can recieve it.

Pauli Exclusion Principle
No 2 electrons in the same atom can have exactly the same 4 quantum numbers.

Hund's Rule
Orbitals of equal energy are each occupied by 1 electron before any orbital is occupied by a second electron.

All electrons in singlyoccupied orbitals must have the (spin)
same spin

Diagonal Rule
 After 18 electrons have been assigned to the orbitals, the normal filling under rule one doesn't apply.

Notations to show how electrons are arranged
 Electron configuration notation
 Orbital notation
 Electron dot diagram
 Noble gas notation

Electron configuration notation
 levels with exponent
 1s^2 2s^2 2p^6, etc.

Orbital notation
Levels with arrows

Electron dot diagram
 Write the symbol for the element
 Identify elements in the HIGHEST ENERGY LEVEL
 Doesn't matter which order the dots are in

Noble gas notation
 Write the symbol for the noble gas which PRECEDES the element in brackets & then list the additional electrons the element contains after.
 [AR]4s^2 3d^10 4p^4