General Chemistry Concepts: FINAL
EXAM
The mass number of an atom is the sum of the protons and neutrons in the nucleus.
True
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Isotopes of a neutral atom differ by the number of electrons.
False- they differ by the number of neutrons
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The lowest energy state for an electron in hydrogen atom is called the ground state.
True
In emission, an electron gains energy by transitioning from a higher energy state to a lower
energy state.
False- they lose energy during this transition
The principal quantum number, n, determines the orientation of an atomic orbital.
False- determines the energy of an atomic orbital
how to to find energy of 1 mole of photons given wavelength
1. units need to agree; if given wavelength in nm, convert to m
,2. find v using c = λv
3. find energy using E = hv
4. for one mole, multiply energy by Avogadro's number (6.022 x 10²³ mol)
quantum number basic rules
1. n is principal quantum number and is used to determine the energy of an electron given its
position according to n
✰ n = 1, 2, 3...→infinity
✰ n cannot be equal to 0 because n=0 would be nucleus, and the electron is never in nucleus
2. l is orbital angular momentum and tells us about shape
✰ l = any integer (0, 1, 2, 3...) → n-1 is the largest value it can have (aka l depends on n)
3. ml is magnetic quantum number, tells us about orientation
✰ ml = -l, -l +1,...0, l-1, l (whole numbers)
✰ for any given value of l, there are 2l + 1 orbitals
4. ms is electron spin quantum number
✰ can only have 2 values: -1/2 or 1/2 (spin up or down)
number of l determines orbital type
determining number of nodes
✺ # total nodes = n-1
✺ # angular nodes = l
✺ # radial nodes = total - angular
given shape and radial wavefunction of an orbital; how to find orbital depicted
1. see where line crosses x axis on graph; this indicates number of radial nodes
2. look at orbital shape to determine number of angular nodes
, 3. remember that total nodes = n-1
4. remember that number of angular nodes = l, and l determines orbital type
explaining the example given:
1. the graph crosses the x axis once, so there is 1 radial node
2. the shape indicates 1 angular node
3. there are 2 total nodes; therefore, 2 = n-1, so n must equal 3
4. because there is 1 angular node, l = 1
5. when l = 1, the orbital type is a p orbital
6. therefore, the orbital depicted is a 3p orbital
ground state
✧ electron configuration = electron's "address"
✧ in ground state, electron configuration specifically refers to a relaxed state: no excited
electrons
Pauli Exclusion Principle
An atomic orbital can only hold at most two electrons, one spinning upwards and one spinning
downward
Aufbau Principle
electrons occupy lowest available energy level (lazy elections)
Hund's Rule
electrons will occupy separate orbitals unless energy considerations force them to occupy the
same orbital.
→ if more than one orbital of a subshell is available, all electrons with parallel spins to each
orbital before pairing the electrons
EXAM
The mass number of an atom is the sum of the protons and neutrons in the nucleus.
True
We have an expert-written solution to this problem!
Isotopes of a neutral atom differ by the number of electrons.
False- they differ by the number of neutrons
Previous
Play
Next
Rewind 10 seconds
Move forward 10 seconds
Unmute
0:00
/
0:15
Full screen
Brainpower
Read More
The lowest energy state for an electron in hydrogen atom is called the ground state.
True
In emission, an electron gains energy by transitioning from a higher energy state to a lower
energy state.
False- they lose energy during this transition
The principal quantum number, n, determines the orientation of an atomic orbital.
False- determines the energy of an atomic orbital
how to to find energy of 1 mole of photons given wavelength
1. units need to agree; if given wavelength in nm, convert to m
,2. find v using c = λv
3. find energy using E = hv
4. for one mole, multiply energy by Avogadro's number (6.022 x 10²³ mol)
quantum number basic rules
1. n is principal quantum number and is used to determine the energy of an electron given its
position according to n
✰ n = 1, 2, 3...→infinity
✰ n cannot be equal to 0 because n=0 would be nucleus, and the electron is never in nucleus
2. l is orbital angular momentum and tells us about shape
✰ l = any integer (0, 1, 2, 3...) → n-1 is the largest value it can have (aka l depends on n)
3. ml is magnetic quantum number, tells us about orientation
✰ ml = -l, -l +1,...0, l-1, l (whole numbers)
✰ for any given value of l, there are 2l + 1 orbitals
4. ms is electron spin quantum number
✰ can only have 2 values: -1/2 or 1/2 (spin up or down)
number of l determines orbital type
determining number of nodes
✺ # total nodes = n-1
✺ # angular nodes = l
✺ # radial nodes = total - angular
given shape and radial wavefunction of an orbital; how to find orbital depicted
1. see where line crosses x axis on graph; this indicates number of radial nodes
2. look at orbital shape to determine number of angular nodes
, 3. remember that total nodes = n-1
4. remember that number of angular nodes = l, and l determines orbital type
explaining the example given:
1. the graph crosses the x axis once, so there is 1 radial node
2. the shape indicates 1 angular node
3. there are 2 total nodes; therefore, 2 = n-1, so n must equal 3
4. because there is 1 angular node, l = 1
5. when l = 1, the orbital type is a p orbital
6. therefore, the orbital depicted is a 3p orbital
ground state
✧ electron configuration = electron's "address"
✧ in ground state, electron configuration specifically refers to a relaxed state: no excited
electrons
Pauli Exclusion Principle
An atomic orbital can only hold at most two electrons, one spinning upwards and one spinning
downward
Aufbau Principle
electrons occupy lowest available energy level (lazy elections)
Hund's Rule
electrons will occupy separate orbitals unless energy considerations force them to occupy the
same orbital.
→ if more than one orbital of a subshell is available, all electrons with parallel spins to each
orbital before pairing the electrons
