Atomic Structure. Chapter 7: Describe the properties of electromagnetic radiation . Understand the origin of light from excited atoms and its relationship to atomic structure. Describe the experimental evidence for wave-particle duality. Describe the basic ideas of quantum mechanics .
Describe the properties of electromagnetic radiation.
Understand the origin of light from excited atoms and its relationship to atomic structure.
Describe the experimental evidence for wave-particle duality.
Describe the basic ideas of quantum mechanics.
Define the three quantum numbers and their relationship to atomic structure.
Frequency – hertz (s-1)
Speed = wavelength (m) x frequency (s-1)
c = l x v
Students should be familiar with conversion of units and conversion between l and v.
h = Planck’s constant
= 6.6260693 x 10-34 J s
E = h v
Light with large l (small v) has a _____ E.
Light with a short l (large v) has a ____ E.
E = h v
No e- observed until light of a certain minimum E is used.
electron should increase with increase
in light frequency—not observed!
minimum E is used.
the number of e- ejected depends on
= RWhich Mathematical Expression represents the Regular Patterns of Emission?
R = 1.0974 x 107 m-1
when n > 2
n = 3 , l =red line
n = 4 , l = green line,
Etc. Balmer Series
An electron (e-) traveled about the nucleus in an orbit.
1. Any orbit should be possible and so is any energy.
2. But a charged particle moving in an electric field should emit energy.
End result should be matter self-destruction!
1.- An electron could occupy only __________ ___________or energy levels in which it is stable.
2.-The energy of the electron in the atom is ______________.
Potential energy of electron
in the nth level
= En = -
∆E = Efinal – Einitial = -R h c
Louis de Broglie (1892-1987) proposed that all moving objects have _______ _________________(1924).
For light: (1) E = mc2
(2) E = h v = h c / l
Baseball (115 g) at 100 mph
e- with velocity = 1.9 x 108 cm/sec
It is possible to observe wave-like properties only for particles of extremely __________, such as protons, neutrons, and electrons.
Wave motion:wave length and nodes
4. In contrast to Bohr’s theory – quantization is imposed as a postulate.
5. The is related to the probability of finding the electron within a given region of space = _______________.
6. Energy is known precisely – position is given by a probability. The region of space in which an electron of a given energy is most probably located is called its _______________.
7. The solution to the Schrödinger's equation, for an electron, in a 3-D space, are 3 integer numbers = quantum numbers n, l, and ml. These numbers have only certain combination of values.
Determines the ________ of the electron. Also related to size of orbital.
En = - Z2h R / n2
Electrons with the same n value are in the same electron ______ or same electron _________.
Determines the ______ at which electrons circulate about the nucleus. Related to orbital __________.
Electrons with the same l value are in the same _______ and have the same orbital _____ (______). All orbitals in the same subshell have the same ___________.
Determines the _____________ of the orbital motion of the electron. (Clockwise or counterclockwise). Related to ___________ in space of the orbitals within a subshell, this gives the ___________ of orbitals in a subshell.
See Table 7.1 (p 319)
Number of subshells in a shell = n
Number of orbitals in a subshell = 2l + 1
Number of orbitals in a shell = n2
l =0 (s) ; l =1 (p) ; l =2 (d) ; l =3 (f)
Name of orbital = value of n and letter code for l
If n=1 ; l = n-1 = 0 ; ml = 0
Only 1 subshell (s); only 1 orbital (1s)
If n=2 ; l = 0, 1 ; ml = +1, 0, -1
There are 2 subshells (s and p)
4 orbitals (the 2s, and three 2p (3 orientations)
surface density plot
or radial distribution plot
Students should be familiar with definitions of quantum numbers and orbital types.