Does the atomic number change for isotopes? And what subatomic particle changes?
No and neutrons
These are the ourtmost electrons on an atom.
Valence electrons
Who proposed that atoms as indivisible units of matter.
Dalton
For each of the following electron subshells, write the # of e- it holds:
s
f
d
p
s-2 e-
p-6e-
d-10e-
f-14e-
Draw the Bohr model for aluminum.

List the 2 types of decay that we discussed in class.
Alpha and beta decay
Which particle is positively charged?
Proton
Who conducted a gold foil experiment and found the nucleus had a positive charge, and this is where most of the mass is for an atom. This model is called the Nuclear model
Rutherford
What are the 3 rules for writing electron configurations?
Fill the lowest energy levels 1st. (Aufbau's)
1 e- in each electron orbital. (Hund's)
Pair electrons up and give them reverse spins (Pauli's)
Draw a wave and label how the wavelength would be measured.

Th-234 undergoes beta decay. Write the equation for this reaction.
23490Th --> 23491Pa + beta particle
What 2 subatomic particles are you using when calculating mass number?
Proton + Neutrons

Bohr discovered that electrons move around the nucleus in fixed orbits. What is the name of this model?
Planetary Model
[Ar]4s23d3
How many neutrons in the follow substance?
What is the element?

20 n0
Potassium
How do we write an alpha particle?
42He
What is the atomic number of Rubidium?
37
This is the accepted model for how electrons move around the nucleus. This was discover by Schodinger et.all. What is the name of this model?
Electron Cloud Model
How many energy levels does Be have?
2 energy levels
High Energy
Calculate the average atomic mass of an unknown element, "Xenotium" (Xn). Use the information form above.
average mass = (23.985 x 0.7899) + (24.986 x 0.1000) + (25.982 x 0.1101)= 24.304970 amu
Thomson used the cathode ray tubes to describe an atom as a sphere with a uniform positive charge and negatively charged electrons scattered throughout the atom. What is the name of this model?
Plum Pudding Model
An electron at ground state has what type of energy associated with it?
The lowest available energy level.
What happens when an electron falls from a higher energy level to a lower energy level?
Energy is release.