GENERAL CHEMISTRY CONCEPTS:
FINAL EXAM
The mass number of an atom is the sum of the protons and neutrons in the nucleus. -
Correct Answers -True
Isotopes of a neutral atom differ by the number of electrons. - Correct Answers -False-
they differ by the number of neutrons
The lowest energy state for an electron in hydrogen atom is called the ground state. -
Correct Answers -True
In emission, an electron gains energy by transitioning from a higher energy state to a
lower energy state. - Correct Answers -False- they lose energy during this transition
The principal quantum number, n, determines the orientation of an atomic orbital. -
Correct Answers -False- determines the energy of an atomic orbital
how to to find energy of 1 mole of photons given wavelength - Correct Answers -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 - Correct Answers -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 - Correct Answers -
determining number of nodes - Correct Answers -✺ # total nodes = n-1
✺ # angular nodes = l
✺ # radial nodes = total - angular
given shape and radial wavefunction of an orbital; how to find orbital depicted - Correct
Answers -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 - Correct Answers -✧ electron configuration = electron's "address"
✧ in ground state, electron configuration specifically refers to a relaxed state: no excited
electrons
Pauli Exclusion Principle - Correct Answers -An atomic orbital can only hold at most two
electrons, one spinning upwards and one spinning downward
Aufbau Principle - Correct Answers -electrons occupy lowest available energy level
(lazy elections)
FINAL EXAM
The mass number of an atom is the sum of the protons and neutrons in the nucleus. -
Correct Answers -True
Isotopes of a neutral atom differ by the number of electrons. - Correct Answers -False-
they differ by the number of neutrons
The lowest energy state for an electron in hydrogen atom is called the ground state. -
Correct Answers -True
In emission, an electron gains energy by transitioning from a higher energy state to a
lower energy state. - Correct Answers -False- they lose energy during this transition
The principal quantum number, n, determines the orientation of an atomic orbital. -
Correct Answers -False- determines the energy of an atomic orbital
how to to find energy of 1 mole of photons given wavelength - Correct Answers -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 - Correct Answers -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 - Correct Answers -
determining number of nodes - Correct Answers -✺ # total nodes = n-1
✺ # angular nodes = l
✺ # radial nodes = total - angular
given shape and radial wavefunction of an orbital; how to find orbital depicted - Correct
Answers -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 - Correct Answers -✧ electron configuration = electron's "address"
✧ in ground state, electron configuration specifically refers to a relaxed state: no excited
electrons
Pauli Exclusion Principle - Correct Answers -An atomic orbital can only hold at most two
electrons, one spinning upwards and one spinning downward
Aufbau Principle - Correct Answers -electrons occupy lowest available energy level
(lazy elections)
