Periodic Trends Flashcards
coulombic attraction
“electrostatic force”:
the force of attraction or repulsion between charged particles
what affects coulombic attraction?
- the signs of the particles
- the distance between the particles
- their charge’s magnitude
if the charge of a particle increases…
the magnitude of electrostatic forces also increases
if the distance between particles increases…
the magnitude of electrostatic force quickly decreases
coulomb’s law
the electrostatic force between two charged particles:
F oc (q1 x q2)/ r^2
(f is the force, q charge of particle)
what is coulomb’s law?
a proportionality
how to find nucleus and e- attraction?
F oc (q nuc x q2)/ r^2
what happens if both charges are the same, or different in coulomb’s law?
same: repulsive force
different: attractive force
shielding is…
when when outer electrons are repulsed by inner electrons, and therefore feel lesser pull towards the nucleus
shielding across and down:
across a period: shielding doesn’t increase a lot (same outer shell)
down a group: shielding increases a lot (extra outer shells, so more inner e-)
effective nuclear charge (zeff)
the amount of charge an electron actually feels from the nucleus
zeff = z - s
Fe
Another aka of electrostatic force / coulombic attraction
across a period
zeff increases, attraction btwn nuc and e-s increases, as shielding up, but nuc charge upup
down a group
zeff increases, distance INCREASES, so attraction decreases (shielding and charge increase, but distance even more)
ionization energy
the E needed to remove 1 e-
e- affinity
the E released when 1 e- is gained
electronegativity
an atom’s tendency to attract e- density in a bond (lower it is, the more it shares e-s)
across a period trends
radius down
IE up
EA up
ENEG up
down a group trends
radius up
IE down
EA down
ENEG down
why is distance more powerful than charge in coulomb’s law?
b/ distance is SQUARED and in the denom (:
IE trends
up in a period b/ it takes more energy to take an e- from more charge, down in a group b/ opposite
jumps for each IE, jumps a LOT if losing a shell
radius trends
down in a period b/ the more p+s, the more the e-s are pulled in, up in a group b/ opposite
EA trends
up in a group b/
electronegativity trends
up in a period b/ more charge means the less it wants to share and down in a group b/ the less charge, the easier it is to share
IE exceptions
- lower when 1 e- is on a higher sublevel (like p vs s) b/ it takes less energy to pull off a single e- in a dif sublevel
- lower when 1 pair of e-s is in one orbital b/ more e- - e- repulsion, and easier to remove
