Chem Unit 4: Electrons
Why does the 4s orbital begin to fill before the 3d orbital?
The 4s orbital is a lower-energy orbital than the 3d orbital
orbital notation
a diagramic representation that uses dashes and arrows to show the principal energy levels and sublevels for all the electrons in an atom
In an electron-dot structure, the element's symbol represents the
atom's nucleus and inner-level electrons
electron and protons _______each other
attract
As an electron gas gets closer to the nucleus the __________ to the nucleus gets _________
attraction, stronger
Pauli's exclusion principle states
no 2 electrons in the same atom can have the same set of 4 quantum numbers
Pauli Exclusion Principle
no two electrons in the same atom can have the same set of four quantum numbers
A(n) ___________________ is the minimum amount of energy that can be lost or gained by an atom.
quantum
The modern model of the atom that treats electrons as waves is called the
quantum mechanical model
which color of visible light has the least energy
red light has the least energy
the characteristic bright-light spectrum of an element is produced when its electrons
return to lower energy levels
Bohr's model and its relationship to atomic spectra.
Bohrs model shows that while the electron of the atom remains in the ground state, its energy is unchanged. When the atom absorbs one or more quanta of energy, the electron moves from the ground state orbit to an excited state orbit that is further away. Energy levels are designated with the variable n. The ground state is n = 1, the first excited state is n = 2, and so on. The energy that is gained by the atom is equal to the difference in energy between the two energy levels. When the atom relaxes back to a lower energy state, it releases energy that is again equal to the difference in energy of the two orbits. This is explained in the Bohr model by the realization that the electron orbits are not equally spaced. As the energy increases further and further from the nucleus, the spacing between the levels gets smaller and smaller.
formula to determine the maximum number of electrons in an energy level
2n^2
How many sublevels are present in the third main energy level?
3
the maximum number of electrons in the 1st principle energy level is 2(4)^2 or
32
which electron transition represents a release of energy?
3p to 1s because the energy is being release to come back down to ground state, when energy is absorbed it makes the energy go to higher levels but when its released it goes back down to lower levels.
there are ___ principle energy levels
4
In which subshell would an electron have the highest energy?
4s because it is the greatest energy level
what is the maximum number of orbitals in the "d" sublevel and "p" sublevel?
5 and 3
how many energy levels actually exist? which has the most
7, and 7
how many electrons are in level 6?
72
example of electron configuration
7N = 1s^2 2s^2 2p^3
the maximum number of electrons in the 1st principle energy level is 2(2)^2 or
8
Orbital
A three-dimensional region around the nucleus that indicates the probable location of an electron
4th Quantum number
- S or Ms
Relationship between wavelength, frequency, wave, speed, amplitude, and energy
- The speed of light is the product of its wavelength and its frequency. - wavelength and frequency are inversely related; in other words, as one quantity increases, the other decreases. - as energy increases the wavelength decreases - as wavelength increases the frequency decreases. - Together all of these factors contribute to the wave and the characteristics it will have.
2nd quantum number
- called sublevel or subshell
Exited electron configurations
- do not follow aufbau's principle - ex: 1s^2 2p^6 3s^2
principle energy level
- n represents the major energy levels of an atom and indicates the probable distance of the electrons from the nucleus
the maximum number of electrons in the 1st principle energy level is 2(3)^2 or
18
short-hand noble gas electron configuration
19 K [Ar] 4s^1
Which electron configuration represents a noble gas?
1s2 2s2 2p6
Which electron configuration represents an atom in an excited state?
1s^2 2s^2 3s^1
The Pauli Exclusion Principle states that an orbital can hold a maximum of ____ electrons
2
the maximum number of electrons in the 1st principle energy level is 2(1)^2 or
2
the maximum number of electrons that a single orbital of the 4d sublevel may contain is
2
the energy level with the principal quantum number (n) of 2 contains a total of
2 sublevels
The maximum number of electrons that can occupy an orbital is ___, provided they have _________
2, opposite sins
Sublevel
An atomic orbital, or collection of atomic orbitals, that occupy a principal energy level and are called s, p, d, and f.
_______________________ states that it is impossible to know both the velocity and the position of a particle at the same time.
Heisenberg Uncertainty principle
The arrangement of electrons in an atom of an element determines the chemical properties of that element. Our present-day understanding of how electrons are arranged in an atom is the result of all of these scientific contributions EXCEPT
Schrodinger's wave equation that predicted atomic orbitals De Broglie's equation that led to thinking of electrons as both particles and waves Bohr's orbits that explained hydrogen's quantized energy states EXCEPT: Rutherford's gold foil experiment that proved the existence of the nucleus
bohr model diagram
Sodium 2e- 8e- 1e-
how is bright-light spectrum produced?
The bright-light spectrum is produced when white light containing all frequencies passes through a gas not enough to be incandescent.
valence electrons
The electrons in the outermost orbital: determine the chemical properties of an element
How does Bohr's model of the atom incorporate Planck's idea of quantization?
Using Planck's constant, Bohr obtained an accurate formula for the energy levels of the hydrogen atom. He postulated that the angular momentum of the electron is quantized because of the quantization, the electron orbits have fixed sizes and energies.
Lewis dot structure
diagram of a molecule using dots to represent valence electrons
D Sublevel is shaped like a ____.
double dumbell
The p sublevel is shaped like a _____.
dumbbell
the highly probably location of an electron within the atom is an
electron configuration
The sum of the superscripts in an electron configuration represents the total number of _______ in an atom
electrons
quanta are fundamental "pieces" of
energy
The neon atoms in a neon sign emit their characteristic color of light as they absorb energy.
false
do electrons have more energy the closer to the nucleus of the atom they are or farther away
farther away
For an electron to move from an energy level close to the nucleus to an energyy level far from the nucleus it would need to ______ energy
gain
The major regions of the electromagnetic spectrum in order of increasing wavelengths
gamma rays, x-rays, uv rays, visible light, infrared rays, and radio waves.
Which of the following electromagnetic waves has photons of the highest energy?
gamma-rays
As an atom moves from the ground state to an excited state, the potential energy of the atom
increases
to write electron configuration
indentify element then write the noble gas (element one row above and farthest to the right) in brackets and write the ground level (the row the element is in) and finish by adding the amount of electrons in element
while drawing bohr models
just put # of electrons in each respected orbital
Drawing Lewis Structures
just put the number of valence electrons around the element symbol
Bright light spectrum (atomic emission spectrum)
light given off by an excited atom with distinct pattern
to find valence electrons
look at periodic table element and at the very bottom or just add the superscripts (electrons) of the highest energy levels
For an electron to move from an energy level far from the nucleus to an energy level close to the nucleus it would need to _______ energy.
lose
the electron has
low mass and negatively charged
The Aufbau Principle states that electrons are added one at a time to the ___________ energy orbitals
lowest
3rd Quantum number
m
the ground state is the __________ stable energy state of an atom
most
_ sublevel has the ________ energy and _________ sublevel has the _________
s, lowest, f, highest energy
number of orbitals in each sublevel
s=1 p=3 d=5 f=7
The S sublevel is shaped like a _____.
sphere
An orbital diagram uses arrows to represent the _____________
spin of electrons
Aufbau Principle
states that an electron occupies the lowest-energy orbital that can receive it
Heisenberg's uncertainty principle
states that it is not possible to know precisely both the velocity and the position of a particle at the same time - relates to electrons in an atom because if an electron got too close to the nucleus, then its position in space would be precisely known and, therefore, the error in measuring its position would be minuscule.
Hund's Rule
states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals
Electron confuguration
the arrangement of electrons in an atom, which is prescribed by three rules- the aufbau principle, the Pauli exclusion principle, and Hund's rule.
ground state
the energy level that an electron normally occupies and is the lowest energy for that electron.
Quantum
the minimum amount of energy that can be gained or lost by an atom. - quantum then becomes known as quantum numbers such as n,l,m,s which are used to describe the general location in an atom
Relationship between Modern Wave Mechanical Model (quantum-mechanical model) and electron configuration
the model states the quantum number which mentions the number of subshells in that level which then leads to the number of orbitals in that subshell which then leads to the number of electrons in the overall element, so when writing out the electron configuration you can see the number of electrons that are in an element and the number of sublevels that must be in the configuration.
second quantum number describes....
the orbital shape within an energy level and shows the sublevels
3rd quantum number describes...
the orientation of an orbital in space. since atoms are 3 dimensional, the orbitals can fall on the X, Y, or Z axis.
When a potassium compound is placed in a flame, energy is released a violet color is produced. This energy release is due to _______________________.
the return of excited electrons to lower energy levels
4th quantum number describes...
the spin of electron in an orbital (opposite directions) and describes the direction of the electron cloud - since both electrons have a negative charge, they repel. When charged particles spin they act like tiny magnets. Since the two electrons spin in opposite directions, one acts like the north pole of the magnet and the other acts like the south pole. This makes the electrons move.
what does it mean for energy to be "quantized"
this means that the electrons can possess only certain discrete energy values
F sublevel is
too complex to describe shape
Each element has a unique atomic emission spectrum.
true
According to Hund's rule, electrons occupy equal energy orbitals so that a maximum number of ____________ results
unpaired electrons
usually the term kernel includes all parts of the atom except
valence electrons
which color of the visible light has the most energy
violet wave have the most energy
excited state
when an electron occupies an energy state greater than its ground state.
Energy formula with wavelength
∆E= h*c/ wavelength - convert wavelength from m to nm then plug number into equation - h= planck's constant: 6.63x10^-34 j*sec -c= speed of light: 3.00x 10^8 m/sec
