Lecture 4 Flashcards
energy
ability to do things
low energy
can’t do something
high energy
has the potential to do something
stuck in a rut
system can have the potential to do something but needs energy
potential energy
look at the diagram
attractive force
makes things closer, pushes to 0
repulsive forces
pushes things away
potential well
energy dip vs distance graph
is something enters it, it ends up at the bottom
energy is needed to get it out of the potential well
balls
governed by gravitational potential energy
atoms
governed by electrostatic potential
electrostatic potential
within an atom
positive nucleus, electrostatic attraction
coulomb’s law
F = q1 x q2/ 4πE0r^2
F
force between particles
q1 and q2
charges on particles
E0
constant
r
distance
large distance between particles
if r= large, r^2 will be very large
diving by a large number, force is small
when the distance is large, interaction is weak
particles get closer
as r decreases, f increases
the interactions between the particles increase as they get closer
charges are the same
like charges repel, f is positive
charges are different
consequence of coluombs law
attractive, f is negative
bonds
hold atoms together, don’t connect them
covalent bonds
very strong, very directional and short range (3 A)
ionic bonds
strong, not directional, medium range (10 A)
r12 = r1 + r2
potential well
check notes
properties of potential well
stable bond: distance of the stable bond length, minimum of the potential well
energy/input is needed to compress of pull the bond apart
bond formation
when a bond is formed, energy is given out (energy decreases)
energy is needed to make a bond (binding energy)
width of the well
distance over which things interact
range of the bond
changing properties, changing wells
check notes
example question
check notes
