Unit 3 - Atoms And Molecules Flashcards
What was John Dalton atomic Theory?
- all elements are composed of atoms
- atoms of same element are alike while atoms of different elements are different
- atoms are indivisible
- atoms of elements combine in the ratios of whole #s to form compounds
What subatomic particle did J.J. Thomson discover?
The electron
What did Robert Millikan do?
He determined the charge on an electron
What did Ernest Rutherford discover?
The proton
+ 3 types of radioactive emissions
What did Neils Bohr use to describe the organization of electrons with an atom?
Quantum Theory, which talked about orbits and energy levels
What did Louis de Beoglie propose?
Wave Model of atom
What did Edwin Schrodinger and Werner Heisenberg contribute?
- Electron Cloud Model
* developed quantum #s
What did James Chadwick discover?
Neutrons
How do you find the mass number?
Atomic number/Number of protons?
Number of neutrons?
- Round atomic mass to nearest while number
- Top left number on element
- Mass # - Atomic # = # of neutrons
What are isotopes?
Atoms with the same # of protons but different # of neutrons
What is the Pauli Exclusion Principle?
No two “e” in the same atom can be described by the same 4 quantum numbers
What is the Aufbau Principle?
Fill lowest energy orbitals first when filling orbitals
What is Hund’s Rule?
The most stable configuration is the one with max # of unpaired electrons with the same spin
What are the 4 quantum numbers?
n = shell; describes energy level
L = subshell; describes shape and type of orbital
mL = orbital; describes the # of electrons in each subshell and their orientation
ms = magnetic spin
What are Intermolecular Forces and the 4 types of those forces?
They are the attractive forces between molecules and between ions and molecules
- Dipole - Dipole
- Hydrogen bonds
- London Dispension Forces
- ion - Dipole forces
What is Polar Covalent?
It’s when electrons are shared unequally between 2 atoms (due to differences in electro Negativity)
What is Hydrogen Bonding?
- a stronger version of a Dipole-Dipole force
* found in molecules containing HYDROGEN and FON (Fluoride, Oxygen, or Nitrogen)
What are Ion-Dipole Forces?
- Attraction force between an ion and a neutral molecule that has a dipole
- most commonly found in solutions
What are London Forces?
Weak force that holds non-polar molecules together when in liquid and solid states
What are Dipole-Dipole Forces?
• Forces of attraction between positively charged ends of polar molecules
What did Mendeleev create?
The original Russian-version Periodic Table, where trends could be seen when the elements were ordered by atomic weight
What is the Trend of Atomic Radius?
DECREASES from L > R across a period
INCREASES from T > B in a group/family
Due to shielding effects and larger orbitals
What is Electronegativity and its trend?
- the attraction an atom has for a shared pair of electrons in a covalent bond
INCREASES from L > R across a period
DECREASES from T > B in a group/family
What is Ionization Energy and its trend?
- energy needed to remove an electron
INCREASES from L > R across a period
DECREASES from T > B in a group/family
What is Electron Affinity and its trend?
- energy associated with the addition of an electron to an atom
INCREASES from L > R across a period
DECREASES from T > B in a family/group
