atomic structure Flashcards
what is the quantum concept? what example do we use to model this?
-energy is present in small, discrete bundles
-a tennis ball that rolls down a staircase loses energy in small bundles- the loss is quantized
what does the Bohr model state about electrons?
an electron can have only certain energy values, called energy levels, that are quantized
what is the equation for the energy in an electron in a hydrogen atom? What does each of the variables stand for
- (-R(sub)H/n^2)
-R(sub)H= 2.179 x 10^-18 J
-n= principle quantum number
what is absorption?
electron gains energy to move to a higher energy level
what is emission?
electron loses energy to move to a lower energy level
what is the equation for an energy change for a hydrogen electron?
-R(sub)H((nf^-2)-(ni^-2))
what is an energy level?
an allowed state that an electron can occupy in an atom
what is a ground state?
lowest energy level available to an electron in an atom (when n=1)
what is an excited state?
an energy state above the grounded state
what is an electron transition?
movement of an electron between energy levels
what are some strengths of the Bohr model (2)?
-accurately predicts energy needed to remove an electron from an atom (ionization)
-allowed scientists to begin using quantum theory to explain matter at the atomic level
what are some limitations of the Bohr model (2)?
-does not account for spectra of multi-electron atoms
-movement of electrons in atoms is less clearly defined than Bohr allowed
what did Werner Heisenberg discover?
-it is impossible to know with absolute certainty both the position, x, and the momentum, p, of a particle such as an electron
-because we can’t know both of these numbers, we describe the location of electrons in terms of probability
what are orbitals? how are they described?
-3-dimensional volumes that have a high probability of finding an electron
-with 4 quantum numbers
what is the principal quantum number? what variable is it represented by? what values can it have?
-number which the energy of an electron in an atom primarily depends
-n
-any positive value
what does it mean if orbitals are in the same shell?
they have the same value for n
what is the angular momentum number? what variable is it represented by? what values can it have?
-distinguishes orbitals of a given n(shell) having different shapes
-l
- 0 to (n-1)
what l value is represented by the s orbital?
0
what l value is represented by the p orbital?
1
what l value is represented by the d orbital?
2
what l value is represented by the f orbital?
3
what is the magnetic quantum number? what variable is it represented by? what vales can it have?
-distinguishes orbitals of a given n and l; a given energy and shape but having different orientations
-m(sub)l
- any value -l…0…+l
what is the spin quantum number? what variable is it represented by? what values can it have?
-the two possible orientations of the spin axis of an electron
-m(sub)s
- -1/2 or +1/2
if n=1 and l=0, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
-0
-1s
-1
if n=2 and l=0, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
-0
-2s
-1
if n=2 and l=1, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
- -1, 0, +1
-2p
-3
if n=3 and l=0, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
-0
-3s
-1
if n=3 and l=1, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
- -1, 0, +1
-3p
-3
if n=3 and l=2, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
- -2, -1, 0, +1, +2
-3d
-5
if n=4 and l=0, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
-0
-4s
-1
if n=4 and l=1, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
- -1, 0, +1
-4p
-3
if n=4 and l=2, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
- -2, -1, 0, +1, +2
-4d
-5
if n=4 and l=3, what are the possible values of m(sub)l? what is the subshell notation?
how many orbitals are in the subshell?
- -3, -2, -1, 0, +1, +2, +3
-4f
-7
what shape is an s-orbital?
a sphere
what does the pauli exclusion principles state?
no two electrons in an atom can have the same four quantum numbers
what is the maximum number of electrons in an s subshell?
2
what is the maximum number of electrons in a p subshell?
6
what is the maximum number of electrons in a d subshell?
10
what is the maximum number of electrons in an f subshell?
14
what is the aufbau principle?
- a scheme used to reproduce the ground-state electron configuration by successively filling subshells with electrons in a specific order
what is an electron configuration?
a shorthand method of writing the location of electrons by sublevel
wat is the order of the electron sublevels in electron configurations (up to 7p)
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p
what is the electron configuration of chromium (Cr)?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹3d⁵
what is the electron configuration of Molybdenum (Mo)?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s¹ 4d⁵
what is the electron configuration for Copper (Cu)?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d¹⁰
what is the electron configuration of silver (Ag)?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s¹ 4d¹⁰
what is a core electron?
all electrons that are not in the outermost energy level
what is a valence electron?
electron in the outermost energy level
given the electron configuration, 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵, what are the valence electrons?
4s² 4p⁵
what is noble gas configuration?
-only the valence electrons are used
-core electrons are represented by the noble gas with the same configuration in brackets
what is the noble gas configuration of Br?
[Ar] 4s² 3d¹⁰ 4p⁵
what do we do when writing the electron configuration for a positive ion?
remove one electron for each positive charge
what do we do when writing the electron configuration for a negative ion?
add an electron for each negative charge
what is the rule for transition metal ions?
atoms generally lose the ns electrons before losing the (n-1)d electrons
what is Hund’s rule?
the lowest-energy arrangement of electrons in a subshell is obtained by putting electrons into separate orbitals of the subshell with the same spin before pairing electrons
what is the periodic law?
when elements are arranged by atomic number, their physical and chemical properties vary periodically
what trend is seen with atomic radius on the periodic table?
-within each group (vertical column), the atomic radius increases with the period number (as it goes down)
-within each period (horizontal row), the atomic radius tends to decrease with increasing atomic number
why does atomic radius increase down groups?
each successive shell is larger than the previous shell
why does atomic radius decrease across the periods?
higher atomic number means more protons and a higher nuclear charge. This increased charge will attract the electron closer to the nucleus
which element has the smallest atomic radius?
neon
what trends are seen with ionic radius?
- cations lose electrons, so there are more protons than electrons, so electrons are more attracted to the nucleus, so their ionic radius decreases
-anions gain electrons so more electrons than protons means there is a weaker attraction
what is effective nuclear charge?
the positive charge that an electron experiences from the nucleus. It is equal to nuclear charge, but it is reduced by shielding or screening from any intervening electron distribution
what trends are seen with effective nuclear charge?
-effective nuclear charge increases across a period
why does effective nuclear charge increase across a period?
because the shell number (n) is the same across a period, each successive atom experiences size decreases across a period
what is first ionization energy?
energy needed to remove the highest-energy (outermost) electron from a neutral atom in the gaseous state, thereby forming a positive ion
what trends are seen with first ionization energy?
-going down a group, first ionization energy decreases
-ionization generally increases with atomic number
why does first ionization energy decrease down a group?
the smaller an atom, the harder it is to remove an electron, so the larger the ionization energy
given the noble gas Li, the ionization energies are as follows
1st- 520
2nd- 7298
3rd-11815
how many valence electrons does Li have
2
in an atom, what is the maximum number of electrons that can have the quantum numbers n=4 and m(sub)s = 1/2?
16
which statement is correct about atomic orbitals and quantum numbers is correct?
a. the maximum number of orbitals with the quantum number n=3 is 18b. there are five 2d orbitals
c. the angular momentum quantum number is related to the shape of the orbital
d. a 4f orbital is not possible
c. the angular momentum quantum number is related to the shape of the orbital
select the sequence of atoms that are correctly listed in order of increasing size
a. F < Br < Ge < K
b. Na < Al < P < S
c. Ba < Ca < Mg < Be
d. Cl < Si < C < B
a. F < Br < Ge < K
select the smallest species
a. Fe3+
b. Fe2+
c. Fe
d. K
Fe3+
select the sequence that is listed in order of increasing size
a. Ar < K+ < Ca2+ < Cl- < S2-
b. Cl- < Ar < K+ < Ca2+ < S2-
c. K+ < Ca2+ < Cl- < S2- < Ar
d. Ca2+ < K+ < Ar < Cl- < S2-
d. Ca2+ < K+ < Ar < Cl- < S2-
from which of these one-electron species is it most difficult to remove an electron?
a. He+
b. Li2+
c. Be3+
d. B4+
d. B4+
list these atoms in order of increasing first ionization energy:
Li, Na, C, O, F
Na, Li, C, O, F
which atom has the highest second ionization energy?
a. K
b. Ca
c. Sc
d. Ba
a. K
an element’s most stable ion forms an ionic compound with chlorine having the formula XCl2. If the ion has 36 electrons, what is the element from which the ion comes?
a. Kr
b. Se
c. Sr
d. Rb
c. Sr
which group on the periodic table forms ions with a 2+ charge when they react with nonmetals/
group 2 elements
how many electrons can be described by the quantum numbers n=3, l=2, m(sub)l=-1
2
which of these gives a correct trend in ionization energy
a. Al < Si < P < Cl
b. Be < Mg < Ca < Sr
c. I < Br < Cl < F
d. Na+ < Mg2+ < Al3+ < Si4+
a. Al < Si < P < Cl
c. I < Br < Cl < F
d. Na+ < Mg2+ < Al3+ < Si4+
what is the correct order from smallest to largest atomic radium of Li, N, F, and Na
F, N, Li, Na
what is the correct ranking from smallest to largest for the first ionization energies of O, F, Na, S, and Cs
Cs, Na, S, O, F
what is the subshell notation when n=3, and l=2
3d
