Atomic Structure and Periodic Trends Flashcards
proton charge
1+
proton mass
1 amu
atomic number
- Z
- number of protons
- nuclear charge
- determines the element
neutrons charge
0
neutrons mass
1 amu
mass number
- A
- number of protons and neutrons
- weighted average all of isotopes
isotope
- differs in number of neutrons
electron charge
-1
electron mass
0 amu
charge
- number of protons and electrons
C>0
cation
C=0
atom
C<0
anion
Bohr model of the atom
- electrons orbit at fixed distances from the nucleus
- distance between orbits decreases with distance from the nucleus
quantization of electron energies
- electron energies are quantized are are related to their fixed radius orbits
- energy increases with distance from the nucleus
principle quantum number, n
- describes the radial distance of an electron’s orbit from the nucleus.
electron transitions excitation
- electrons absorb only specific, allowed quantities of energy
- allowed energies match the energy difference between an electron’s ground state and excited state.
- initial promotion most difficult
electronic transitions relaxation
- electrons in an excited state can return to a lower energy orbit, emitting a photon equal in energy to the energy difference between the energy levels.
- electrons can return to the ground state in a single transition, or in multiple transitions.
hydrogen absorption spectrum
- dark bands on a light background
hydrogen emission spectrum
- bright bands on a dark background
lowest to highest energy of waves in electromagnetic spectrum
- radio
- micro
- IR
- ROYGIV
- UV
- Xray
- Gamma
energy of a photon
E = hf = (hc)/λ
quantum model of the atom
- electrons exist within 3-D orbitals of various sizes and shapes
- electron energies are quantized and are related to their specific orbital
- four quantum numbers fully describe the electronic structure of the quantum model
quantization of electron energies
- energy increases with distance from the nucleus
- energy increases with complexity of the orbital shape
energy shell and subshell
- each period corresponds to a different energy shell
- each shell is higher energy and larger than the last.
- each block corresponds to a different energy shell
- each subshell is more complex and higher energy than the last.
magnetism and spin
- each subshell higher than s has multiple orbital orientations
- each orbital orientation has the same energy
- each orbital can only hold up to 2 electrons
- each electron can be spin up or spin down
Aufbau principle
- electron added to orbitals from lowest to highest energy
- valence electrons are in the highest energy shell
- electrons first removed from valence orbitals (outermost) from highest to lowest energy
Hund’s rule
- electrons fill degenerate orbitals one per orbital before pairing
- occupy singly before pairing
paramagnetic
- at least one electron is unpaired
- attracted to a magnetic field
diamagnetic
- all electrons are paired
- doesn’t like magnetic field
Pauli principle
- no two electrons may be identical
- this limits the occupancy of an orbital to a maximum of 2 electrons.
column 4 and 9 of d-block
- remove the first electron from the highest s subshell first then add to d subshell.
- then remove the rest from the d subshell.
excited state of electron configuration
- any number of configurations that have higher energy than the lowest energy electron configuration
- make sure the configuration has the correct total number of electrons
- the electrons can be in ANY orbital as long as that orbital exists.
effective nuclear charge (Zeff)
- the nuclear charge experienced by valence electrons
- the pull of protons on valence electrons
- reduced due to shielding
- increases from left to right and from bottom to top on the periodic table. Points to NY
atomic radius
- as the force increases, valence electrons are pulled more strongly toward the nucleus, decreasing atomic radius
- increases from right to left and top to bottom on the periodic table. atomically hot in death valley
ionic radius
- valence electron repulsion is slightly increased in anions
- valence electron repulsion is slightly decreased in cations.
- ionic radius increases with increasing negative charge
shielding
- core electrons shield the valence electrons from the full nuclear charge
- the nuclear charge experienced by a valence electron is Zeff
ionization energy
- the minimum amount of energy required to remove the outermost electron from an atom
- increases from left to right and bottom to top
- less energy to pull of an electron as they are further from the nucleus with increasing atomic radius
- hard to do from for nobel gases.
electron affinity
- energy change to add an electron to an atom.
- most elements release energy upon the addition of an electron
- the larger the energy change, the more stable the resulting ion
- becomes more negative from left to right and bottom to top
multiple ionization
- as the charge on a given ion increases, so too does its ionization energy
- as the extent of ionization increases, valence electron repulsion decreases.
- the second ionization energy is greater than the first.
electronegativity
- the ability of an atom to attract electrons to itself in a covalent bond
- increases from left to right and from bottom to top
- F>O>N>C>O>L>Br>I>S>C=H
Acidity
- the measure of a compound’s ability to lower the pH of a solution, donate protons or accept electrons
- depends on the relative stability of the acid and its CONJUGATE BASE!
- as the size of the anion increases, its stability increases
- increases from left to right and from top to bottom on the periodic table. Points to Florida where there is a lot of acidic orange juice.
d block
- transition metals
s and p blocks
- representative elements
f block
- rare earth metals