Atomic Structure and Periodic Trends Flashcards
What letter is given to denote atomic number
Z aka # protons in that element
What letter is given to denote atomic mass
A
In the Bohr Model of the atom, e- orbit at fixed distances from the nucleus. The distance between the orbits _____ (increases or decreases) with distance from the nucleus
decrease therefore the distance between n = 1 and n = 2 is larger than the distance between 2 and 3
Electrons in an excited state can return to a lower energy orbit, emitting a ____ equal in energy to the energy difference between the energy levels
photon
Distinguish between the hydrogen absorption spectrum and the hydrogen emission spectrum
H absorption: dark bands against a colorful background; signify which colors are absorbed by H; thus e- are gaining energy and are becoming excited H emission: bright colored bands against a dark background; signify which colors are emitted by H; thus e- are losing energy and becoming relaxed
Equation for Energy
E = hf = hc/lambda
What is the order of the electromagnetic spectrum from lowest to highest energy?
radio, micro, IR, ROYGBV, UV, Xray, gamma
What number is denoted by the shell and subshell
shell = principle quantum number = n subshell = orbital type = s,p,d,f
What is the Pauli Principle?
no two e- may be identical; this limits the occupancy of an orbital to a max of 2 e-, each with an opposite spin
What is the Aufbau Principle?
e- are added to orbitals from lowest to highest energy; consequently, e- are first removed from orbitals from highest to lowest energy (starting with highest energy valence orbitals) exception: even though 3d is higher in energy than 4s, the valence 4s e- are removed before the non-valence 3d e-
What is Hund’s rule?
e- fill degenerate orbitals with one e- per orbital before pairing i.e. px, py, and pz orbitals will each be filled with one e- with the same spin before a second e- with the opposite spin is added to fill each px, py, and pz orbital
Chromium and copper both have anomalous e- configurations, [Ar]4s13d5 and [Ar]4s13d10 respectively. Why?
The d subshell is more stable when it is half filled or fully filled, and so will steal an e- from the 4s orbital to do so.
Which ion is more stable, Fe2+ or Fe3+? Why?
Fe3+ is more stable because its e- configuration is [Ar]3d5, compared to Fe2+ which is [Ar]3d6
____ e- shield the val e- from the full nuclear charge
core
The nuclear charge experienced by a valence e- is called ____ _____ charge
effective nuclear charge, Zeff
Moving L to R across a period, which of the following increase, decrease: 1) electrostatic attraction of val e- ______ 2) atomic radius _____ 3) ionization energy _____ 4) electron affinity _____ 5) electronegativity _____ 6) acidity level ______
1) decreases 2) decreases 3) increases 4) increases 5) increases 6) increases
How does atomic radius change when moving from top to bottom down the periodic table?
increases
How does ionization energy change when moving from top to bottom down the periodic table?
decreases
How does electron affinity change when moving from top to bottom down the periodic table?
decreases
How does acidity change when moving from top to bottom down the periodic table?
increases
The ionic radius _____ (increases or decreases) with increasing negative charge
increases
What is ionization energy?
the minimum amount of energy required to remove the outer most e- from an atom in its gaseous state
As Fe increases, removal of e- requires ____ (less or more energy)
more
How is ionization energy affected as the positive charge on a given ion increases?
ionization energy will also increase, as it will (in most cases) be harder to remove successive e- from the atom
What is e- affinity?
the energy change when adding an e- to the valence shell of an atom in its gaseous state
Most elements tend to ___ energy upon the addition of an e-
release
As Fe increases, additional e- releases ____ (less or more) energy
more
Elements with ____ configurations tend to require energy upon the addition of an e-
closed-shell or closed-subshell
As Fe increases, the electronegativity (or ability to attract e- _____ (decreases or increases)
increases
If energy is released when the e- is added, the usual convention is to say that the electron affinity is ____
negative
If energy is required when the e- is added, the usual convention is to say that the electron affinity is ____
positive
Which family group tends to have the largest negative electron affinity values?
Group 7: halogens
Which 2 family groups tend to have the largest positive electron affinity values?
Group 1: alkaline earth metals Group 8: noble gases
What is the structure of a binary acid?
HX
Distinguish between alpha, beta, and gamma decay
alpha: emits an alpha particle (nucleus loses 2 p+ and 2 n); atomic # decreases by 2 and atomic mass # decreases by 4; alpha particles are relatively weak, as they can be stopped by skin or clothing beta: three types, all involve a conversion of a p+ into a n or vice versa (depending if nucleus has too many p+ or n); more dangerous than alpha particles d/t decreased mass and higher energy gamma: occurs when the overexcited nucleus returns to its ground state, releasing a gamma photon (which has no mass nor charge and is simply just an expulsion of energy); the most type of dangerous decay
Distinguish between the 3 types of beta decay
B- decay: neutron converts into a p+ by releasing a B- particle (aka e- gets ejected); atomic # increases by one B+ decay: p+ converts into a neutron by emission of a positron (aka antiparticle, which is identical to an e-, but opposite charge); atomic number decreases by one electron capture: p+ converts into neutron by stealing an e- from the innermost shell; atomic number decreases by 1
The shorter the half life, the ____ the decay constant, k
greater
What is nuclear binding energy?
The energy released when individual nucleons are bound together to form the nucleus
The ______ (lesser or greater) the nuclear binding energy per nucleon, the more stable the nucleus
greater
what is mass defect?
Refers to the mass that is converted to energy by nucleons when they are bound together to form the nucleus. Therefore, the mass of the nucleus is less than the sum of all the masses of the individual nucleons. This difference is the mass defect.
Equation for energy of a photon
Ephoton = hf = hc/lambda
h = Planck’s constant = 6.63 x 10-34 J·s
f = frequency
c = speed of light = 3 x 108
lambda = wavelength
Note that Energy and frequency are inversely proportional to lambda/wavelength: the longer the wavelength, the less energy and less frequency of the photon
All p orbitals of x, y, and z are known as degenerate orbitals. What does this mean it regards to their energy?
means that they are equal in energy
What is effective nuclear charge, Zeff
The nuclear charge experienced by a valence e-
Moving from top to bottom of the periodic table, Zeff and # of valence e- _____ (increases, decreases, or stays the same). What happens to the electrostatic attraction, Fe, going down a group in the periodic table and why?
1) stays the same
2) Fe decreases even though Zeff remains constant because the size of the valence shell (r) increases. Coulombs law: Fe = (Zeff + C)/r2
Moving from L to R across the periodic table, the Zeff and # of valence e- ______ (increase, decrease, or remains the same). How is Fe affected?
1) increase (this is because the size remains fairly constant; therefore the effective nuclear force decreases)
2) Fe increases because as Zeff increases, the size of the valence shell stays the same
How does atomic radius change moving from L to R accross a periodic table?
it decreases
Distinguish between diamagnetic and paramagnetic
Dia: an atom that has all of its e- spin paired; therefore it must have an even number of e- AND have all of its occupied subshells filled. This creates no net magnetic field and these atoms are actually repelled by an applied external magnetic field
Para: an atom that doesn’t have all of its e- paired or subshells filled. These atoms will be attracted to an externally applied magnetic field.
