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CHAPTER 8 ELECTRON CLOUD AND PROBABILITY
8-1, 8-2, 8-3, 8-4, 8-5, 8-6, 8-7, 8-8, 8-9, 8-10, 8-11, 8-12, 8-13, 8-14
Bohr's theory of the atom was revised to include the fine lines of the hydrogen spectrum
DeBroglie suggested that particles have characteristics of waves -it was proven 2 years later BACK TO THE TOP
8-2 The Apparent Contradiction
Electrons can act like particles and like waves
2 sided nature of waves & particles is called wave particle duality of nature
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Momentum=mass*velocity p=mv
as the momentum of an object increases its wavelength decreases
Quantum mechanics describes the behavior of extremely small particles traveling at velocities near that of light
Speed of ground state e- is 2.19X10(6)m/s BACK TO THE TOP
8-4 Measuring position and momentum
Heisenberg uncertainty principle-the exact position and momentum of an object cannot be determined at the same time BACK TO THE TOP
Schrodinger developed a mathematical equation that described the wave like behavior of the electron
The 4 quantum numbers in schrodingers equation are used in describing electron behavior
Probability is ratio between # times e- is in that position divided by the total # times it is at all possible positions BACK TO THE TOP
8-6 Wave-mechanical view of the hydrogen atom
Schrodinger's equation can be used to describe the most probable positions of the hydrogen electron
the position of the electron can best be represented by a cloud
Because of its high speed the electron occupies all the volume defined by the path through which it moves-this volume is called the electron cloud BACK TO THE TOP
8-7 Solving Schrodinger's equation
He+ and H(2)+ are two one electron systems for which Schrodinger's equation has been solved
quantum numbers represent different electron energy states
each electron within an atom can be described by a unique set of four quantum numbers
each electron in an atom can be described by a unique set of 4 quantum numbers, n,l,m,s. BACK TO THE TOP
The principle quantum number,n, corresponds to the number of the energy level-SHELL, ORBIT BACK TO THE TOP
8-9 Energy Sublevels and orbitals
The second quantum number describes the sublevels in energy level
the number of sublevels in an energy level equals the value of the principle quantum number
sublevels are named, s,p,d,f(named for sharp, principal, diffuse, and fundamental)
s can hold a pair of e-(2), p can hold 3 pairs, d can hold 5 pairs, and f can hold 7 pairs
a pair of electrons is called an orbital BACK TO THE TOP
8-10 Shape of the electron cloud
the size of the charge cloud is not controlled by any single factor
orbitals of the same energy are said to be degenerate
the third quantum number, m, describes the orientation in space of each orbital
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8-11 Distribution of Electrons
each orbital may contain a pair of electrons
Pauli's exclusion principle states that no two electrons in an atom can have the same set of four quantum numbers
two electrons can occupy the same orbital only if they have opposite spins.
electrons in the same sublevel tend to occupy empty orbitals rather than pair with another electron
Hund's rule-electrons will enter each orbital of equal energy until all of the orbitals contain one electron, the electron spins are parallel in these orbitals
electrons normally occupy the set of orbitals giving the atom the lowest energy
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8-12 Order of filling sublevels
the 4s fills before the 3d
the arrow diagram on page 157 shows order of filling also use the "ENERGY NUMBER METHOD S=1 P=2 D=3 F=4 ADD SHELL PLUS SUBSHELL EQUAL NUMBERS FILL FROM INSIDE TO OUTSIDE. ELECTRONS ARE LIKE MANY OF YOU THEY WILL GO INTO THE AREA WHERE THEY CAN EXPEND THE LEAST AMOUNT OF ENERGY BACK TO THE TOP
Usually only outer energy level electrons are involved in chemical change
In an electron dot diagram, the symbol represents the nucleus and all electrons except those in the outer level
the dots in an electron dot diagram indicate paired and unpaired electrons in the outer energy level BACK TO THE TOP
the electron can be thought of as a particle, wave, or a negatively charged cloud
scientist do not have a single, completely satisfactory description of the structure of atoms BACK TO THE TOP
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