Chapter 6: Electronic Structure of Atoms
Electronic structure: the arrangement and energy of electrons.
Electromagnetic radiation moves as waves through space at the speed of light.
Wavelength (λ): the distance between corresponding points on adjacent waves.
Frequency (v): the number of waves passing a given point per unit of time.
The longer the wavelength, the smaller the frequency. Example:
Top wave = low frequency, long wavelength
Bottom wave = high frequency, short wavelength
All electromagnetic radiation travels at the same velocity.
The speed of light (c) is 3.00×108 m/s
c=λv
3.00×108 m/s = (wavelength)(frequency)
Energy is proportional to frequency
E=hv
Plank’s constant (h) is 6.626×10−34 J⋅s
Describes where electrons are located around the nucleus of an atom.
Moves diagonally
1s2 → 2s2 → 2p6 → 3s2 → 3p6 → 4s2 → 3d10 → 4p6 → 5s2 → 4d10 → and so on
H: 1s1
Has 1 total electron
He: 1s2
Has 2 total electrons
Li: 1s22s1
Has 3 total electrons
Be: 1s22s2
Has 4 total electrons
B: 1s22s22p1
Has 5 total electrons
C: 1s22s22p2
Has 6 total electrons
N: 1s22s22p3
Has 7 total electrons
O: 1s22s22p4
Has 8 total electrons
F: 1s22s22p5
Has 9 total electrons
Ne: 1s22s22p6
Has 10 total electrons
The periodic table is broken up into four blocks: s, p, d, and f.
Columns 1-2 and He are a part of the s block
The transition metals (columns 3-12) are the d block
Columns 13-18 make up the p block
The lower elements are part of the f block
The row indicates the highest occupied electron level.
The columns gives the outermost electron configuration (the superscript)
Quantum mechanics: describes the movement of electrons.
Orbitals: describes a spatial distribution of electron density.
An orbital is described by a set of four quantum numbers.
The principle quantum number, n, describes the energy level on which the orbital resides.
The values of n are integers greater or equal to 1.
n = 1, 2, 3, … ∞ ≥1
These correspond to the values in the Bohr model.
This quantum number defines the shape of the orbital.
Allowed values of l are integers ranging from 0 to n-1
Letter designate the different values of l. This defines the shape of the orbitals.
Value of l | Letter used |
---|---|
0 | s |
1 | p |
2 | d |
3 | f |
The magnetic quantum numbers described the three-dimensional orientation of the orbital.
Allowed values of ml are integers ranging from -l to l including 0.
−l≤ml≤l
There can be up to 1 s orbital, 3 p orbitals, 5 d orbitals, and 7 f orbitals.
Orbitals with the same value of n form an electron shell.
Different orbitals types within a shell are subshells.
insert picture
The values of l for s orbitals is 0
Spherical in shape
Radius of the sphere increases with the value of n
Electronic structure: the arrangement and energy of electrons.
Electromagnetic radiation moves as waves through space at the speed of light.
Wavelength (λ): the distance between corresponding points on adjacent waves.
Frequency (v): the number of waves passing a given point per unit of time.
The longer the wavelength, the smaller the frequency. Example:
Top wave = low frequency, long wavelength
Bottom wave = high frequency, short wavelength
All electromagnetic radiation travels at the same velocity.
The speed of light (c) is 3.00×108 m/s
c=λv
3.00×108 m/s = (wavelength)(frequency)
Energy is proportional to frequency
E=hv
Plank’s constant (h) is 6.626×10−34 J⋅s
Describes where electrons are located around the nucleus of an atom.
Moves diagonally
1s2 → 2s2 → 2p6 → 3s2 → 3p6 → 4s2 → 3d10 → 4p6 → 5s2 → 4d10 → and so on
H: 1s1
Has 1 total electron
He: 1s2
Has 2 total electrons
Li: 1s22s1
Has 3 total electrons
Be: 1s22s2
Has 4 total electrons
B: 1s22s22p1
Has 5 total electrons
C: 1s22s22p2
Has 6 total electrons
N: 1s22s22p3
Has 7 total electrons
O: 1s22s22p4
Has 8 total electrons
F: 1s22s22p5
Has 9 total electrons
Ne: 1s22s22p6
Has 10 total electrons
The periodic table is broken up into four blocks: s, p, d, and f.
Columns 1-2 and He are a part of the s block
The transition metals (columns 3-12) are the d block
Columns 13-18 make up the p block
The lower elements are part of the f block
The row indicates the highest occupied electron level.
The columns gives the outermost electron configuration (the superscript)
Quantum mechanics: describes the movement of electrons.
Orbitals: describes a spatial distribution of electron density.
An orbital is described by a set of four quantum numbers.
The principle quantum number, n, describes the energy level on which the orbital resides.
The values of n are integers greater or equal to 1.
n = 1, 2, 3, … ∞ ≥1
These correspond to the values in the Bohr model.
This quantum number defines the shape of the orbital.
Allowed values of l are integers ranging from 0 to n-1
Letter designate the different values of l. This defines the shape of the orbitals.
Value of l | Letter used |
---|---|
0 | s |
1 | p |
2 | d |
3 | f |
The magnetic quantum numbers described the three-dimensional orientation of the orbital.
Allowed values of ml are integers ranging from -l to l including 0.
−l≤ml≤l
There can be up to 1 s orbital, 3 p orbitals, 5 d orbitals, and 7 f orbitals.
Orbitals with the same value of n form an electron shell.
Different orbitals types within a shell are subshells.
insert picture
The values of l for s orbitals is 0
Spherical in shape
Radius of the sphere increases with the value of n