1st John Flashcards
how is the periodic table set out
order of atomic number
number of protons
what atoms in the periodic table are electronically similar
atoms in the same group
theyre chemically similar
group 18
noble gases
group 1
alkali metals
group 2
alkali earth metals
main group elements
outer shells consist of s and p orbitals
s or p block elements
d metals
partially full d orbital metals.
centre of periodic table
f metals consist of
lanthanides (4f)
actinides (5f)
bottom two rows
what can the schrodinger equation not do
find solutions for multi electron systems
what do we do bc the schrodinger cant find solutions to multi electron systems
we apply the hydrogen stuff to multi electron systems
what do we need to know when applying hydrogen to multi electron systems
same quantum numbers are used
orbitals have the same shapes(radial and angular wave functions)
radial functions are similar to hydrogen (depend on n and l tho)
pauli exclusion principle
electrons must have opposite spins
no 2 electrons in an atom can have the same 4 quantum numbers
n, l, ml, ms
aufbau principle
electrons are filled from lowest energy to highest energy
we remove from highest energy to lowest energy
hunds first rule
for degenerate orbitals, electrons must be added to different degenerate orbitals with parallel spins.
eg: fill in the 3 2p orbitals with 1 electron each parallel.
parallel spins are more stable as they minimise coloumbic repulsion
what does degenerate mean
the same in energy
what does the energy in H depend on
the principle quantum number
n
what does the energy in multi electron systems depend on
principle quantum number, n
angular quantum number, l
angular quantum number = azimuthal quantum number, l.
seen by radial distribution graph
what is the probability of finding an electron at distance r from nucleus in RDF proportional to
4 pi r squared psi squared
in rdf, is 1s max closer to nuc than 2s max
yes!!
meaning 1s shields 2s from nuc charge (not very well tho)
meaning 1s is a smaller orbital
in rdf how is 2s seen
m shape
smaller first hill
larger than 1s bc more further out
penetrates 1s orbital, e- are closer to nuc bc of this (although 2s dont rlly shield 1s)
1 radial node
what is the max in a rdf curve
the most probable area to find an electron
what is the value for psi at a radial node
0
means than e- are closer to the nuc
what is a core electron
electrons in a filled orbital
dont take part in chemical reactions
they shield valence electrons
low energy
close to nucleus
what is a valence electron
highest energy electron
they do chemsitry
get shielded by core electrons
order of orbital shielding strength
s
p
d
f
s shields best as it has a sphere shape.
what is shielding dependednt on in multi electron systems
principle quantum number
angular quantum number, l
shielding
electrons experience a lower nuclear charge (Zeff) due to e- closer to the nucleus repelling them.
depends on quantum number n.
larger n = larger shielding = lower Zeff
penetration
refers to the electron density of an electron around the nuc.
2s has more e- density near nuc than 2p so 2s is more penetrating
depends on principle and angular quantum number
electrons in orbitals haveee
different wavefunctions
therefore
different rdf
penetrating effect strength when n is the same
s
p
d
f
aufbau and why 2s is filled before 2p exp. rdf
2s penetrates 1s
meaning more e- density near nuc than 2p (and some of 1s)
mini max closer to nuc meaning lower in energy than 2p.
1s shields 2p more than 2s, 2s penetrates 2p and 1s, mini max closer to nuc, lower in energy
4s filled before 3d exp. rdf + aufbau
4s penetrates 3d
some 4s e- closer to nuc than 3d
filling 4s reduces shielding, 4s feels greater Zeff, lower in energy, more stable.
closer to nuc = lower energy = more stable
Zeffective = effective nuclear charge
Zeff = Z - S