1. Chapter 4 Arrangement in Electrons in Atoms
By Connor Campbell
Lindsay Fisher
Paul Gonzalez 
Sonya McCormick
Nick Solomon

2. Section 1: The Development of the New Atomic Model
Properties of Light
The Wave Description of Light
Electromagnetic Radiation: a form of energy that exhibits wavelike behavior as it travels through space
Electromagnetic Spectrum: formed by all of the electromagnetic radiations
Other types of electromagnetic radiation include: X-rays, ultraviolet and infrared light, microwaves and radio waves

3. All forms of electromagnetic radiation move at a constant speed of 3
All forms of electromagnetic radiation move at a constant speed of 3.0 x 10^8 m/s
Wavelength (λ): the distance between corresponding points on adjacent waves Frequency (v): the number of waves that pass a given point in a specific time, usually one second
Expressed in waves/second
Measured in hertz

4. Speed of Light Equation         
              
             C = λv
speed of light = wavelength * frequency

5. The Photo Electric Effect
Photoelectric Efficent: refers to the emission of electrons from a metal when light shines on the metal
The Particle Description of Light Quantum: the minimum quantity of energy that can be lost or gained by an atom

6. E = hv energy = Planck’s constant * frequency
Energy of a Wave:
E = hv      energy = Planck’s constant * frequency 
Planck’s constant (h) = * 10^-34

7. Photon: A particle of electromagnetic radiation having zero mass and carrying a quantum of energy   Ephoton= hv
In order for an electron to be ejected from a metal surface the electrons must be struck by a single photon possessing at least the minimum energy required to knock the electron loose
Different metals are bound more or less tightly therefore different metals require different minimum frequencies

8.  The Hydrogen-Atom Line-Emission Spectrum
Ground State: the lowest energy state of an atom
Excited State: a state in which an atom has a higher potential energy than it its ground state

9. When an excited atom returns to its ground state, it gives off the energy it gained in the form of electromagnetic radiation
When a narrow beam of the emitted light was shined through a prism, it was separated into a series of specific frequencies (and therefore specific wavelengths, λ=c/v) of visible light

10. Line-Emission Spectrum: the band of light produced from emitted light being shown into a prism
Continuous Spectrum: the emission of a continuous range of frequencies of electromagnetic radiation 
Attempts at explaining why hydrogen atoms give off only specific frequencies of light is known as the quantum theory
The energy of the photon emitted from an excited electron going back to ground state is (Ephoton = hv) is qual to the difference in energy between the atom’s initial state and its final state

11. Atomic Orbitals and Quantum Numbers
Schrödinger Equation: Specifies the properties of an electron.
Quantum Numbers: Show the properties of atomic orbitals and the electrons in those orbitals.

12. Principal Quantum Number
Symbolized by n, and represents an electron’s main energy level.
Only has positive integer values.
The higher the principal quantum number is, the more energy the electron has, and the farther away from the nucleus it is.
The number of sub-orbitals in an electron shell is equal to n2.

13. Angular Momentum Quantum Number
All electron shells, except the first, have sub-levels that exist as differently shaped orbitals.
Symbolized by l.
Can have a value of 0, or be less than n-1.
Values of l correspond to different orbital shapes.

14. Angular Momentum Quantum Number (cont.)
Orbital Shape s 1 p 2 d 3 f
s orbital is spherical
p orbital is shaped like a dumbbell
d orbital is shaped like a flower, or two intersecting p orbitals

15. Magnetic Quantum Number
Represented by m.
Shows the orientation of the different orbitals.
s orbitals, as spheres, only have one orientation.
Other orbitals can be oriented on one of 3 different axises, x, y, or z.

16. Spin Quantum Number Has a value of either +1/2 or -1/2
Shows the direction an electron spins about its internal axis
Each orbital can hold two electrons spinning in opposite directions.

17. Rules Governing Electron Configuation
electron configuration- the arrangement of electrons in an atom
 Aufbau principle- an electron always occupies the lowest energy orbital that can receive it
 Paulie exclusion principle- no two electrons in the same atom can have the sam four quantum numbers
 Hund's rule- orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin state

18. Representing Electron Configurations
Orbital Notation
each orbital is represented by at least one line
the orbital can have at most two electrons per line, with the first one pointing up and the second one pointing down
for example, 1s is written under the line representing the first orbital

19. Electron Configuration Notation
no lines
level number, orbital letter, superscript for number of electrons
for example, 1s2
this means that there are 2 electrons in the s orbital of the first level

20. Elements of the 2nd Period
highest occupied number- the electron-containing main energy level with the highest principal quantum number
inner-shell electrons- electrons that are not in the highest occupied energy level
2nd period elements have electrons that occupy the the second energy level 

21. Elements of the 3rd Period
noble gases- group 18 elements
noble gas configuration- an outer main energy level fully occupied, in most cases, by 8 electrons
all elements in the 3rd period and below can be written in noble-gas notation
write the name of the noble-gas in the period before in brackets
write the element's remaining electrons in electron configuration notation
ex.: Na is [Ne]3s1

22. Elements of the 4th Period
The elements in the fourth period are the first elements to include the d-orbital in their electron configuration.
The noble-gas notation of elements of the fourth period is done with the following steps.
1. Argon in brackets symbolizing 3s^2 3p^6.
2. The 4s orbital, followed by the 3d orbital, then the 4p orbital.
There are some elements in the fourth period that don't follow Hund's rule in their electron configuration such as; 
Chromium 4s^1 3d^5.

23. Elements of the Fifth Period
The elements of the fifth period follow the electron configuration of the fourth period, however instead of 4s,3d, and 4p, it is 5s, 4d, and 5p.
There are some elements that don't follow the expected electron configuration, when the configuration has the lowest possible energy.

24. Elements of the 6th and 7th Periods
The 6th period is the largest period out of any of the preceding periods, containing 32 elements.
The elements of the 6th period have an f orbital, containing up to 14 electrons.
The noble-gas notation would be;
1. Xenon in brackets symbolizing 6s^2 5d^1 4f^1
Then the 4f orbital, the 5d orbital, and finally the 6p orbital.
 The 7th period is incomplete and is mostly synthetic elements.