Chemistry test 2

Names from the Video 

Greeks - eyes work like flashlights & shoot rays out

Euclid - discovered that light mostly traveled in straight lines deciphered geometry of how light bent and reflected

Ivan Al-Haytham - (first true scientist to study light as he actually did experiments) proved light existed outside the body

Ole Romer - discovered light traveled at a speed (through the fact that an eclipse happened later than what had been predicted

William Herschel - discovered “invisible light” (by noticing the hot temperature past the color red)

Johann Ritter - discovered higher energy past purple

James Clerk Maxwell - discovered light was not a mechanical wave but an electromagnetic wave through the fact that its speed and the speed of electromagnetic waves were the same. Introduced idea of the electromagnetic spectrum

Newton - associated with the particle theory, also discovered white light was made up of spectrum of colors

Christian Hyenes - believed in wave model

Max Planck - said energy was spread across spectrum in little bits he called quanta

Einstein - Realized that light being particles explained the photoelectric effect so he said light had wave particle duality

Electromagnetic Radiation - form of energy that exhibits wavelike behavior as it travels through space

• Visible light is a form of Electromagnetic Radiation

Electromagnetic Spectrum - all forms of Electromagnetic Radiation come together to form

Wavelength ( λ) - the distance between corresponding points on adjacent waves 

Frequency (𝜈) - the number of waves that pass a given point in a specific time, usually one second

Electromagnetic Radiation

• Wave terms, Order and Types (in terms of energy)

• Radio

• Microwave

• Inferred

• Visible

• UV

• X-ray

• Gamma Ray

Know how to do problems involving relationship w/^

5 Laws (who & what say)

Heisenburg’s Uncertainty Principle: you can not know the speed and location of a moving object at the same time

• “It is impossible to determine simultaneously both the position and velocity of an electron or any other particle”

Schrodinger’s Wave Equation: equation allowing us to talk about the probable location in any electron with 4 variables 

(n, l, m, s)

Pauli Exclusion Principle: no 2 electrons in the same atom can have 4 identical quantum numbers

• “No two electrons in the same atom can have the same set of four quantum numbers.”

Quantum Theory - “describes mathematically the wave properties of electrons and other very small particles”

• Quantum Numbers - “Specify the properties of atomic orbitals and the properties of electrons in orbitals

• Principal Quantum Number - “symbolized by n, indicates the main energy level occupied by the electron”

• Angular Momentum Quantum Number - “symbolized by l, indicates the shape of the orbital.”

• Magnetic Quantum Number - “symbolizes by m, indicates the orientation of an orbital around the nucleus”

• Spin Quantum Number - “has only two possible values–(+½, -½)–which indicate the two fundamental spin states of an electron” 

Aufau Principle - when placing electrons start with the lowest energy level and orbital and build up

• “An electron occupies the lowest-energy orbital that can receive it”

• Neils Bohr

Hund’s Rule - when placing electrons in the same energy level and orbital put one in each before going  back and doubling them up

• “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.”

Know Values for variables 

• N: principle quantum number

• L: n-1 (Ex. if N is 2. L is 1 (bc 2-1=1))

• M: +L -> 0  -> -L (Ex. if L is 2, M is -2 -> +2)

• S +/- ½

Orbit v Orbital

• Orbit is the circular path of one thing around another and orbital is an area of high probability for the electron to be

• Orbital - “3-dimensional region around the nucleus that indicates the probable location of an electron”

Shapes of Orbitals

• S orbital: 1 lobe

• P Orbital: 2 lobes

• D Orbital: 4 lobes

• F Orbital: 8 lobes

Bohr Model

Electrons Orbit around the nucleus in energy levels/shells

2 Problems:

• If electrons were constantly spinning around the nucleus they would want to fly off but would be pulled back by the nucleus, this would cause energy loss which would give off light and eventually cause atom to collapse (all atoms do not give off light and are not all collapsed)

When the electrons release energy in electromagnetic waves these waves would interfere 

• Constructive interference: increase energy

• Destructive interference: decrease energy

Why we see the hydrogen spectrum

Electrons within the hydrogen atom are losing energy in specific consistent patterns which is letting off its violet, indigo, blue, and red light

• Why is this important?

  • Shows that the light given off by an element can show what the elements electrons are doing

Be able to do Orbital notation, Electron Configuration, Noble Gas Shorthand, and Electron dot formula

Know Exceptions

• Chromium

• Copper
  

Electron Configuration - the arrangement of electrons in an atom

Nobles Gasses - Group 18 Elements, (He, Ne, Ar, Xe, Ra) 

Noble-Gas Configuration - refers to an outer main energy level occupied, by eight electrons