1: atomic & nuclear structure Flashcards
bohr’s model, correct and incorrect
e- in orbits, infinite number of them
incorrect: orbitals, not orbits
correct: energy is quantized in each orbit(al)
4 orbital types
s: spherical (1)
p: dumbbell (3)
d: 4 leaf clover (4 of them) and 5th is weird 2 lobes separated by circle tube thing
f: hoo cares
nucleus, z + n
z: protons
n: neutrons
z+n = mass n
z = atomic number
atomic mass on PTE
avg of all naturally occuring isotopes; lever rule to determine atomic mass from natural abundancies
PTE, groups = columns, chemically similar
I, II, VIII, VII
I: alkali metals: basic, very reactive (redox explosion with H2O)
II: alkaline earth metals: basic soln in H2O, not as reactive as group I
VIII: noble gases: inert
VII: halogens
electron configuration overview
orbitals = 1s 3p 5d 7f; each one holds 2e-
- every shell has n^2 orbitals
- n=shell number=principle quantum number
- max electrons = 2n^2
- groups I and II: s (1st 2 e-)
- groups III-VIII: p (next 6 e-)
- transition metals: d (10)
exceptions (5, transition metals)
Cr: [Ar]4s1.3d5 Mo: [Kr]5s1.4d5 Cu: [Ar]4s1.3d10 Ag: [Kr]5s1.4d10 Au: [Xe]6s1.5d10
cation formation, how?
remove e- from highest shell first
ex: Zn: [Ar]4s2.3d10 –> [Ar]3d10
how do you find what neutral atom is based off of excited state?
just add up all electrons and you have atomic number, example of excited state– [Ar]4s1.3d10.6p1
magnetism: para vs dia
paramagnetic: unpaired e-; attracted to magnetic field — more unpaired e- = more paramagnetic
diamagnetic: all paired e-; deflection from magnetic field
what does an odd or even number of e- tell you in terms of magnetism
odd = para (unpaired)
even = no info
orbital filling
-degenerate orbitals = equal in energy
-each degenerate orbital gets 1 e- before any of them get 2e-
-everything up to the noble gas is all paired/filled – core electrons
-past these = valence, outermost shell, highest in energy
***once d shell is full, it is part of previously filled core shell (based on NUMBER)
so, Br [Ar] 4s2.3d10.4p5 has 7 valence e-
d shell rules, once it is full…then what?
it is part of previously filled shell, based on number, and its electrons are not considered valence
ex: Br[Ar] 4s2.3d10.4p5 has 7 valence e-
Pauli Exclusion Principle
no 2e- have same 4 quantum numbers
quantum numbers:
n: principle q#, shell #
l: azmithal, subshell (0=s, 1=p, 2=d, 3=f)
ml: magnetic – specific orbital
ms: spin up or down, +-1/2
range of quantum numbers
n: 1->infinity
l: 0->(n-1)
ml: -l –> +l
ms: 1/2 or -1/2
azmithal numbers mean what
subshell: 0=s 1=p 2=d 3=f
electron energy levels – QUANTIZED
lowest = closest to nucleus
higher energy = excited, farther from nucleus
each shell # corresponds to n
absorb a photon of light (exact correct amount!) and e- jumps to higher shell – only certain energies to absorb/emit for n1–>2, n1–>4, etc
how did they determine composition of sun? absorption spectrum application
sun = 75% H
- take white light (all colors) and shine through H gas, then open up the light that comes through the other side with a prism and see what colors are missing (they were absorbed by H)
- those colors had exact amount of energy between H levels
- white from sun through prism, same colors missing
- *absorption spectrum is unique for every element
emission
fall in energy, relax to lower state, emit photon
ID element by exciting w/electricity adn watching electron fall - because it gives off certain colors/energies of light and based on those, you can ID element
higher energy means what in terms of wavelength and frequency
high energy = high freq, low wavelength
nuclear structure
protons (+) and neutrons
protons repel each other, but strong nuclear force holds them together
relation between mass and penetrating power of nuclear particles
as mass decreases, pentrating power increases (so gamma rays have highest and alpha particles have lowest)
nuclear particles: 5 types
alpha particle: He nucleus, no e-, 2 pro and 2 neu, +2 charge, mass = 4
p: proton, +1 charge, mass =1
n: neutron, 0 charge, mass = 1
b = electron, -1 charge, mass = 0
gamma = no mass or charge
characteristics of stable nuclei: 3 of them
- even # protons and/or neutrons – pair up spins = higher stability
- n/z ratio ~1 (if z<20) – belt of stability (past Ca, does not apply)
- magic #s (2, 8, 20, 50, 82, 126) - # nucleons added up
nuclear rxn: parent –> daughter(s) + energy - mass
E=mc^2 accounts for mass loss
- stronger because more energy in nucleus than electron clouds
- daughter = more stable than parents
- matter and energy are different forms of the same thing
E=mc^2 application
m: kg
c: m/s (speed of light)
E: joules
all products of nuclear rxns are lighter than parents because energy release comes from conversion of mass to energy
5 routes of decay
- alpha decay: reduce mass #, emit alpha particle (2p + 2n) – large nuclei, z>83
- beta decay/emission: n–>p, convert neutron to proton when n/z is too high, atomic number goes UP 1, when above belt of stability
- positron emission: p–>n, convert proton to neutron n when N/Z is too low, atomic number goes down 1 (below belt)
- electron capture: convert a p–>n for same reasons as above
- gamma decay: when nucleus falls from excited to ground state, gives off gamma ray. gamma ray is product
what is one difference of electron capture than other 4 types of decay
particle is a REACTANT – add e- to a proton to make a neutron and drop atomic number by 1
kinetics of nuclear decay
1st order, constant half life (t1/2), rate is proprtional, lnN=lnN(nought)-kt
highest nuclear binding energy per nucleon?
56/26 Fe - MOST STABLE NUCLEUS
- lighter nuclei want to fuse to get closer (fusion, center of star)
- heavier nuclei want to divide (fission)
NBE = nuclear binding energy
energy supplied by the strong nuclear force that holds nucleus
how much energy is given off in nuclear reaction
E = (delta)mc^2
delta m = mass defect
