final Flashcards
What are the two categories of mixtures? Difference between them?
Heterogeneous vs homogeneous. Heterogeneous mixtures are a physical combination that aren’t uniform, while homogenous mixtures are uniform.
What are the 6 phase changes and which phases do they indicate changes to/from?
Melting (s to l), Vaporizing/boiling (l to g), Subliming (s to g), Depositing (g to s), condensing (g to l), and freezing (l to s).
How can mixtures be separating?
Heterogeneous mixtures can be separated by centrifugation or filtration. Homogeneous mixture can be separated using differences in phase change temperatures (eg. distillation, evaporation)
Intensive vs. extensive properties?
Intensive properties stay the same no matter the amount of a substance (eg. density, hardness). Extensive properties depend on the amount of a substance present
(eg. mass, length, width, volume).
Precision vs accuracy.
Precision measures the consistency of results, and is related to the amount of random error in a measurement. Accuracy measures how close results are to the “correct” value, an dis related to the amount of systematic error.
What are the key points of John Dalton’s atomic theory?
Elements are made of atoms, and different elements are composed of different kinds of atoms (i.e. atomic structure dictates properties of different elements)
What were the results of the Cathode Ray Tube Experiment?
Electros are negatively charged (because they are attracted to a positively charged plate). The charge to mass ratio of an electron is 1.71 x 10ˆ11 (highly charged and very light)
What is the plum pudding atom model?
An atom is a spherical cloud of positive charge with negatively charged electrons.
What are alpha and beta particles?
Beta particles have the same charge to mass ratio and negative charge as electrons, making them high energy electors. Alpha particles have twice as much charge and opposite sign as an electron (+2), also 10^3 times heavier.
What kinds of particles were used in the gold foil experiment?
Alpha particles
What were the crucial outcomes of the gold foil experiment?
Most alpha particles passed directly through the gold foil, meaning most of the space in the gold empty was empty (at least of positive charge, which would have repelled alpha particles).
What atomic model came from the gold foil experiment. Describe the model.
The nuclear model: Positive charged all in the atomic nucleus (center), surrounded by a cloud of electrons (negatively charged)
Where are protons neutrons and electrons found in the atom?
Protons and neutrons found in nucleus, while electrons are outside the nucleus
What are orbitals?
The 3D areas of space that electrons can occupy around the nucleus.
How many electrons are in each orbitals?
Two electrons
How are orbital energies determined?
By their distance from the nucleus.
What does it mean for electron energies to be quantized?
Electrons can only exist at certain energy levels as determined by the orbitals
What are the quantum numbers?
Principal quantum number, angular momentum quantum number, magnetic quantum number, and spin quantum number
What does the principal qn indicate, and what are some “rules” for the principal quantum number?
“n” indicates relative size and energy of a group of orbitals in an atom. Must be a positive integer, orbitas with the same n are in the same shell, orbitals with the same n have same # of nodes, and total number of nodes in an orbital is n-1.
What does the angular momentum qn indicate, and what are some “rules” for the angular momentum quantum number?
“l” defines the shape of the orbital. Must be an integer with value from 0 to n-1. Value of l is number of angular nodes. Orbitals with same n and l as each other are in the same subshell. l=0 is s, l=1 is p, l=2 is d, l=3 is f.
What do we call orbitals with the same energy?
Degenerate
What does the magnetic qn indicate, and what are some “rules” for the magnetic quantum number?
“m1” Defines orientation of an orbital in the space around the nucleus. Must be an integer with value from -l to l. Also defines how many degenerate orbitals exist for each value of l (eg. if l=2, d orbital; 5 m1 values; 5 d orbitals for each shell n)
What does the spin magnetic qn indicate, and what are some “rules” for the spin magnetic quantum number?
Describes whether the magnetic field is spin up or down. ms can be -/+ 1/2. We can write an orbital as a box or line, and show that it contains a spin up/down electron, or both. Each orbital can have have one spin up/down electron, or both, but never two spin up electrons or two spin down electrons.
Does each electron in an atom have a unique set of quantum, numbers?
Yes
For same l value, higher n indicates _____ energy
higher
What is a node?
AN area where no electron can exist
Differences between radial and angular nodes.
Radial nodes are spherical, while angular nodes are planes or cones. Radial nodes never pass through the nucleus, while angular nodes always pass through the nucleus.
Increase in nodes means an _____ in the energy of the orbital
increase
How to determine number of angular nodes?
Same as l value
How are s and p orbitals shaped, respectively
spherical vs. dumbell-like/two lobed
What are the main groups on the periodic table?
Main group elements (alkali metals, alkaline earth metals, post transition metals, metalloids, nonmetals, halogens, noble gases) transition metals, and lanthanides & actinides
Which blocks of elements on the period table correspond to a orbital letter?
Alkali metals + alkaline earth metals (+ H and He) : S-block
Noble gases, Halogens, nonmetals, metalloids, post transition metals: P-block
Transition metals: D-block
Actinides and lanthanides: F-block
How do we write condensed electron configurations?
Take the last element on the row above (in brackets), and write the following orbital configurations. For example: Oxygen
original e configuration: 1sˆ2 2sˆ2 2pˆ4
condensed: [He]2sˆ2 2pˆ4
How do we write the valence electron configuration?
By writing only the electrons in the last shell. For main group elements only s and p orbitals are included in the valence electron configuration
What is an exchange interaction?
When electrons witht he same spin in degenerate energy orbitals can exchange with each other
What does the Econfig equation (42p) - aex mean?
There are four electrons at the 2p level, and energy (ex) is subtracted from the total energy of the configuration.
What are the exceptions to Hund’s rule?
Cr, Cu, Mo, Ag, and Au
Why are there exceptions to Hunds rule?
In those cases, putting the electron in the 3d orbital requires less (exhange) energy than putting it in the 4s energy level.
When forming anions and cations, where do the electrons get added/removed to/from?
For anions, electrons are added to the highest-n partly filled orbitals. For cations, electrons are removed from the highest n orbital