1. The earliest models 2. Smaller than the Smallest 3. The Rutherford Model 4. The Bohr Model 5. Spectra 6. Wave Mechanics Take notes over each video. Check calendar for due date.

 __________________- weighted average of the masses of its constituent isotopes  Ex 2) Naturally occurring chromium consists of four isotopes. It is 4.31% Cr, mass = amu, 83.76% Cr, mass = amu, 9.55% Cr, mass = amu, and 2.38% Cr, mass = amu. Calculate the atomic weight of chromium.

 Ex. 3)Naturally occurring Lithium exists as two isotopes, 6 Li (mass = amu) and 7 Li (mass = amu). The atomic weight is amu. Which isotope is more abundant? Why?

 Ex 4) The atomic number of boron is amu. The masses of the two naturally occurring isotopes 5 10 B and 5 11 B, are and amu, respectively. Which isotope is most common? Calculate the fraction and percentage of each isotope. › requires a little algebra › remember X + (1-X) = 1

1. Always fill orbitals in ________ energy level first. (Aufbau Principle) __________________________- The electron that distinguishes an element from the previous element enters the lowest energy atomic orbital available. (in other words fill one energy sublevel before moving up) 2. No two e- can have _________ 4 quantum numbers in an atom. (____________________________________) Wolfgang Pauli › No two electrons in an atom may have identical sets of 4 quantum numbers.

3. _____________ e- out on a sublevel if possible. (Hund’s Rule) Electrons will spread themselves out among the orbitals individually and give unpaired, parallel spins. The pairing of electrons is an __________________ process; energy must be __________________ in order to make it occur. Exception: If you can achieve full or half-full orbitals by moving one e- between s ~ d or s ~ f orbitals, do so. It’s ______ in energy because there is an increased _____________due to the decrease in the screening of electron/nuclear attractions

1 st row Orbital Order 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p 8s

2 nd row

3 rd row

4 th row

4 th row continued

 ______________________ is an analytical technique that measures the mass-to-charge ratio of charged particles. It is most generally used to find the ____________ of a sample by generating a mass spectrum representing the masses of sample components. The ____________________is measured by a mass spectrometer. wao0O0_qM

This technique is applicable in:  ___________ unknown compounds by the mass of the compound molecules or their fragments  determining the _______________________of elements in a compound  determining the structure of a compound by _________________its fragmentation  ______________ the amount of a compound in a sample using carefully designed methods  studying the fundamentals of gas phase ion chemistry (the chemistry of ions and neutrals in vacuum)  ________________other important physical, chemical, or even biological properties of compounds with a variety of other approaches

relationship for electromagnetic radiation c =  c = ____________________= 3.00 x 10 8 m/s

 Max Planck - __________ › energy is quantized › light has particle character  Planck’s equation

 Ex. 6) What is the frequency of green light of wavelength 5200 Å ?

 Ex. 7) What is energy of a photon of green light with wavelength 5200 Å ?

Albert Einstein explained the ____________________________in 1905 › 1921 Nobel Prize in Physics  electrons are _______________b/c energy from a photon transfers to e - during collisions. If you increase energy, more electrons get kicked off. Each individual photon makes a spark, 1 e - per photon. The more intense the light, the more photons. Light strikes the surface of various metals and causes ______________ to be ejected.

________________________ electric current passing through a gas in a vacuum tube (at very low pressure) causes the gas to_______light emission or bright line spectrum

___________________________ shining a beam of white light through a sample of gas gives an ______________ spectrum shows the wavelengths of light that have been ____________

use spectra to __________ elements can even identify elements in_____

Light of a characteristic wavelength (& frequency) is ________ when electron ____ from ________ E (orbit) to ________ E (orbit) origin of emission spectrum light of a characteristic wavelength (& frequency) is ____________ when electron ________ from ________ E (orbit) to _________ E (orbit) origin of absorption spectrum

 how atoms ________ to us” › we have to interpret their language  Bohr, Schrodinger, and Heisenberg were some of the first scientists to translate the language of atoms

 Ex. 8) An orange line of wavelength 5890 Å is observed in the emission spectrum of sodium. What is the energy of one photon of this orange light?

 Werner Heisenberg › ________________________________  It is ________________ to determine simultaneously both the position & momentum of an electron. Why? The act of measuring a very small particle changes its position, so it is _____________ to precisely determine both the ___________ and _______________ of that object. › electron microscopes use this phenomenon › devices for detecting motion of electron disturbs its position

 There are four ___________ numbers which describe the relative position and energy of an electron in an atom. 1 st ____________ quantum number 2 nd ____________________quantum number 3 rd ______________ quantum number 4 th _______ quantum number

 Symbol “_____” – refers to energy level n = 1, 2, 3, …   The principal quantum number describes the ________________from the nucleus. It is often referred to as ______________or _______  electron’s ________depends principally on n

 angular momentum, tells __________ of the atomic orbitals  _______________- ________of space where the _________________of finding an electron around an atom is _____________ ~ volume that the electrons occupy ___________of the time

 symbol ___ to find ℓ plug into n-1 If n=1 ℓ =0 If n=2 ℓ = 0, 1 If n=3 ℓ = 0, 1, 2 If n=8

 represents the ______ within an energy level: s, p, d, f (code letters for the shapes of orbitals) è s=0 è p=1 è d=2 è f=3  Quantum number - ℓ (in theory) If ℓ = 0, 1, 2, 3, 4, 5, (n-1) Then ℓ = s, p, d, f, g, h, (n-1)

u s orbitals are __________ in shape. u Every energy level has an s orbital  s orbitals have angular momentum quantum number ( l ) equal to 0.  For s:

 p orbitals are shaped like dumbbells or peanuts.  They are oriented along the x, y, and z coordinates.  ______________________  They have an angular momentum quantum number ( l ) equal to 1. For p: 3 per n level, p x, p y, p z

p orbitals

 _______________________  4 clover leaf shaped and 1 peanut shaped with a doughnut around it on Cartesian axes and rotated 45 o For d:  5 per n level

 __________________  most complex shaped orbitals  7 per n level, complicated names For f:  important effects in lanthanides & actinides

 3 rd quantum number  symbol m l  Helps tell _______________ of orbitals m l = - l to + l  Look at _____________________to help you with m l

l =0 m l =0 › only 1 value for s orbital l =1 m l = -1, 0, 1 › 3 values for p orbitals l =2 m l = -2, -1, 0, 1, 2 › 5 values for d orbitals l =3 m l = › 7 values for f orbitals

 4 th quantum number, symbol = _______ › m s = +1/2 or -1/2  tells us the ________ and _____________ of the ____________ field of the ____________

 spin effects › every orbital can hold up to two electrons › one spin up  one spin down   spin describes the ______________of their ________________ field  e- have charges  two _________________ magnetic states

 paired electrons have spins unaligned  › no net magnetic field  Called ____________________ - __________by a magnetic field, all electrons are __________  unpaired electrons have their spins aligned  or  › enhanced magnetic field  Called ________________- ___________to a magnetic field, has _____________electrons

 Let’s find the complete set of quantum numbers for the electrons in Na and Fe (look at electron configurations/orbital diagrams 1 st )  11 Na › must have one set of 4 quantum numbers for each of the 11 electrons in Na

 26 Fe › should have one set of 4 quantum numbers for each of the 26 electrons in Fe

 __________________– lowest energy/most stable state of an atom, molecule, or ion. Fills one sublevel before moving up, follows Aufbau Principle.  _____________– orbitals skipped, does not follow Aufbau Principle  _____________________– very wrong or not possible

 _______________ – different elements that have the same electron configuration b/c of gaining or losing electrons.  ___________________- negatively charged electrons prevents higher orbital electrons from experiencing the full nuclear charge by the repelling effect of inner-layer electrons  ________________________- the net positive charge experienced by an electron in a multi-electron atom

 _______________________ elements: group __ (the last electron fills s or p levels)  IA – alkali metals  IIA – alkaline earth metals  IIIA – boron famly  IVA – carbon family  VA – pnictogens or nitrogen family  VIA – chalcogens or oxygen family  VIIA – halogens  VIIIA – noble gases

 __________________________(filling d level)  3 - the scandium family  4 - the titanium family  5 - the vanadium family  6 - the chromium family  7 - the manganese family  8 - the iron family  9 - the cobalt family  10 - the nickel family  11 - the coinage or copper family  12 - the zinc family  Lanthanide series (filling 4f level)  Actinide series (filling 5f level)

Extra credit 1) In a universe far far away, the laws of quantum mechanics are the same as ours with one small change. Electrons in this universe have three spin states, -1, 0, and +1, rather than the two, +1/2 and -1/2, that we have. What two elements in this universe would be the first and second noble gases? (Assume that the elements in this different universe have the same symbols as in ours.)

2) A) What is the atomic number of the element that should theoretically be below Ra? B) Its chemical behavior would be most similar to which elements? C) How many valence electrons would it have? D) Its electron configuration would be? E) An acceptable set of 4 quantum numbers for the last electron in this element would be? F) What would you name it?