Chemistry Atomic and Molecular Structure Flashcards
The ___ is the basic building block of matter, representing the smallest unit of a chemical element
atom
The ___ and neutrons in an atom form the nucleus, the core of the atom
protons
The ___ exist outside the nucleus in characteristic regions of space called orbital
electrons
According to John Dalton, all ___ are composed of very small particles called atoms
elements
According to John Dalton, all ___ are composed of atoms of more than one element
compounds
According to John Dalton, for any given compound, the ___ of the numbers of atoms of any two of the elements present is either an integer or a simple fraction
ratio
According to John Dalton, a given chemical reaction involves only the ___, combination, or rearrangement of atoms; it does NOT result in the creation or destruction of atoms
separation
The ___ (Z) of an element is equal to the number of protons found in an atom of that element
atomic number
___ carry no charge and have a mass only slightly larger than that of protons, so they can still be considered to have a mass of approximately 1 u
neutrons
Different ___ of one element have different numbers of neutrons but the same number of protons
isotopes
The farther the ___ electrons are from the nucleus, the weaker the attractive force of the positively charged nucleus and the more likely the valence electrons are to be influenced by other atoms
valence
Therefore, the atomic number indicates the number of ___ in a neutral atom
electrons
A positive or negative ___ on an atom is due to a loss or gain of electrons; the result is called an ion
charge
Note that a (+) charge indicates a loss of negatively-charged electrons , whereas a (-) charges indicates a ___ of electrons
gain
The atomic ___ (A) of an atom is equal to the total number of nucleons (protons an neutrons)
mass number
mass number (A) = number of protons + ___
number of neutrons
On a larger scale, the ___ is the weight in grams per one mole (mol) of a given element (g/mol)
molecular weight
A ___ is a unit used to count particles and is represented by Avogadro’s number, 6.02 x 10^23 particles per mol
mole
___ are referred to either by the convention described above or, more commonly, by the name of the element followed by the mass number
isotopes
In 1900, Max Planck developed the first ___, proposing that energy emitted as electromagnetic radiation from matter comes in discrete bundles called quanta
quantum theory
The ___ of the electron is related to its orbital radius: the smaller the radius, the lower the energy state of the electron
energy
At the ___ level, the electron is in its lowest energy state
ground state
Because each element can have its electrons excited to different distinct energy levels, each element possesses a unique ___, which can be used as a fingerprint
atomic emission spectrum
When an electron is excited to a higher energy level, it must ___ energy
absorb
The ___ absorbed as an electron jumps from an orbital of low energy to one of higher energy is characteristic of that transition
energy
The excitation of electrons in a particular element results in energy absorptions at ___ wavelengths
specific
Thus, in addition to an ___, every element possesses a characteristic absorption spectrum
emission spectrum
Absorption spectra can thus be used in the identification of elements present in a gas ___ sample
phase
While the concepts put forth by Bohr offered a reasonable explanation for the structure of the hydrogen atom and ions containing only one ___ (such as He+ and Li2+), they did not explain the structures of atoms containing more than one electron
electron
Due to the flaws in the Bohr model, this is because Bohr’s ___ does not take into consideration the repulsion between multiple electrons surrounding one nucleus
model
An orbital is a ___ of the probability of finding an electron within a given region
orbital
In the current ___ description of electrons, pinpointing both the exact location and momentum of an electron at any given point in time impossible
quantum mechanical
The idea of an electron’s position not being quite known, this idea is best described by the ___ which states that it is impossible to simultaneously determine, with perfect accuracy, the momentum (defined as mass times velocity) and the position of an electron
heisenberg uncertainty principal
Concerning the Heisenberg uncertainty principal, this means that if the ___ of the electron is being measured accurately, its position will not be certain, and vice versa
momentum
___ states that any electron in an atom can be completely described by four ___: n, l,m sub l, and m sub s
modern atomic theory
Furthermore, according to the pauli exclusion principle, no two ___ in a given atom can possess the same set of four quantum numbers
electrons
The ___ and energy of an electron described by its quantum numbers is known as its energy state
position
The ___ of n limits the values of l, which in ___ limit the values of m sub l
value
The values of three of the ___ qualitatively give information about the orbitals: n about the size, l about the shape, and m sub l about the orientation of the orbital
quantum numbers
Think of the ___ as becoming more specific as one goes from n to l to m sub l to m sub s
quantum numbers
The first quantum number is commonly known as the ___ and is denoted by the letter n
principal quantum number
The first quantum number, this is the quantum number used in Bohr’s model that can theoretically take on any positive integer value and represents the ___ where an electron is present in an atom
shell
The maximum n that can be used to describe the ___ of an element at its ground state corresponds with that element’s period (row) in the periodic table
electrons
Nitrogen is in period 2, so neutral Nitrogen in its ground state has ___ with n values of 1 and 2
electrons
The larger the integer value of n, the ___ the energy level and radius of the electron’s orbit
higher
The ___ number of electrons in an electron shell n is 2n^2
maximum
The difference in energy between ___ shells decreases as the distance from the nucleus increases
adjacent
The ___ difference between the third and fourth shells (n=3 and n=4) is less than that between the second and third shells (n=2 and n=3)
energy
The second quantum number is called the ___ and is designated by the letter l
azimuthal (angular momentum) quantum number
The second quantum number, this tells us the shape of the ___ and refers to the subshells or sublevels that occur within each principal energy level
orbitals
For any given n, the ___ of l can be any integer in the range of 0 to n-1
value
The four ___ corresponding to l=0,1,2,and 3 are known as the sharp, principal, diffuse, and fundamental subshells, or s,p,d, and f subshells respectively
subshells
The greater the value of l, the ___ the value of the subshell
greater
However, the ___ of subshells from different principal energy levels may overlap
energies
For example, the 4s subshell will have a lower energy than the 3d subshell because its average distance from the ___ is smaller
nucleus
The first two columns (of the periodic table) show the atoms that have their ___ electrons in the s subshell
valence
The right “block” of the ___ table represents atoms that are filling the six spaces in the p subshell
periodic
Columns 3-12 represent the d block, and the Lanthanide and ___ series are the f block
Actinide
The third quantum number is the ___ and is designated m sub l
magnetic quantum number
As far as the third quantum number is concerned, this number describes the orientation of the ___ in space
orbital
An orbital is a specific ___ within a subshell that may contain no more than two electrons
region
The ___ specifies the particular orbital within a subshell where an electron is highly likely to be found at a given point in time
magnetic quantum number
The possible ___ of m sub l are all integers from l to -l including 0
values
Therefore, the s subshell (l=0), has only one possible ___ of m sub l (0) and will contain one orbital; in contrast, the p subshell (l=1) has three possible m sub l values (-1, 0, +1) and three orbitals
value
The d subshell (l =2) has five possible m sub l values (-2,-1,0,+1,+2) and five orbitals; the f subshell (l=3) has seven possible m sub l values (-3,-2,-1,0,+1,+2,+3) and contains ___ orbitals
seven
The ___ and energy of each orbital are dependent upon the subshell in which the orbital is found
shape
A p subshell with its three possible m sub l values (-1,0+1) has three dumbbell-shaped orbitals that are ___ in space around the nucleus along the x, y, and z axes
oriented
Each p subshell has these three ___, they are often referred to as p sub x, p sub y, and p sub z
orbitals
The fourth quantum number is also called the ___ and is denoted by m sub s
spin quantum number
The ___ of a particle is its intrinsic angular momentum and is a characteristic of a particle
spin
The two spin orientations are ___ +1/2 and -1/2
orientations
Whenever two electrons are in the same orbital, they must have opposite spins due to the ___ exclusion principle
pauli
Electrons in different ___ (different m sub l values) with the same m sub s values are said to have parallel spins
orbitals
Electrons with opposite spins (different m sub s values) in the same orbital (same m sub l value) are often ___ to as paired
referred
For a given atom or ion, the pattern by which ___ are filled and the number of electrons within each principal level and subshell are designated by an electron configuration
subshells
In ___ notation, the first number denotes the principal energy level, the letter designates the subshell, and the superscript gives the number of electrons in that subshell
electron configuration
According to the ___ principle, subshells are filled from lowest to highest energy, and each subshell will fill completely before electrons begin to enter the next one
aufbau
The (n+l) rule is used to ___ subshells by increasing energy
rank
Pertaining to the (n+l) rule, this rule states that the lower the sum of the first and second ___, the lower the energy of the subshell
quantum numbers
If two ___ possess the same (n+l) value, the subshell with the lower n value has a lower energy and will fill first
subshells
Similar to a greyhound bus filling up, ___ will go to empty orbitals before pairing up
electrons
In the case of uncharged atoms, the number of ___ equals the atomic number
electrons
If the atom is ___, the number of electrons is equal to the atomic number plus the extra electrons if the atom is negative or the atomic number minus the missing electrons if the atom is positive
charged
In ___ that contain more than one orbital, such as the 2p subshell with its three orbitals, the orbitals will fill according to Hund’s rule
subshells
Hund’s rule states that, within a given ___, orbitals are filled such that there are a maximum number of half-filled orbitals with parallel spins
subshell
Electrons “prefer” empty orbitals to half-filled ones because a pairing ___ must be overcome for two electrons carrying repulsive negative charges to exist in the same orbital
energy
The presence of paired or unpaired electrons affects the chemical and ___ properties of an atom or molecule
magnetic
If the material has unpaired electrons, a magnetic field will ___ the spins of these electrons and weakly attract the atom to the field
align
___ which have aligned magnetic fields and that have electrons which weakly attract the atom to the field are paramagnetic
materials
Materials that have no unpaired ___ and are slightly repelled by a magnetic field are said to be diamagnetic
electrons
The valence electrons of an atom are those electrons that exist in its outer ___ shell or that are available for chemical bonding
energy
For elements in Groups IA and IIA, only the ___ s electrons are valence electrons
outermost
For elements in Groups IIIA through VIIIA, the outermost s and p electrons in the highest energy ___ are valence electrons
shell
For transition elements, the valence electrons are those in the outermost s subshell and in the d subshell of the ___ energy shell
next-to-outermost
For the inner transition elements (the lanthanide and actinide series), the valence electrons are those in the s subshell of the outermost energy shell, the d subshell of the next-to-outermost energy shell, and the f ___ of the energy shell two levels below the outermost shell
subshell
Atoms with half-filled and ___subshells are extremely stable
fully-filled
Atoms with half filled and fully filled ___ are stable, so much so that some molecules will move electrons from a lower energy subshell into higher one to half fill the subshell
subshells
For ___: it would be expected to have a valence shell configuration of 4s2 3d4. However, if it moves one s electron into the d subshell, then both subshells will be half filled. So, in reality, Cr exists as 4s1 3d5. The same thing is true for all other elements in column 6
chromium
All atoms in column 11 will move one electron to complete the d subshell and, as a result, have a half-filled s ___Copper (Cu) will exist as 4s1 3d10
subshell
