Chapter 2 and 3.2-3.3 Flashcards
What is electromagnetic radiation?
the energy that behaves like a wave and travel at the speed of light in a vacuum, it is LIGHT in a 3D sense
Light traveling includes what
magnetic and electric fields at the same time
What are the 3 characteristics of waves?
wavelengths, frequency. speed
What is the wavelength symbol?
λ (lambda)
What is a wavelength?
distance between 2 peaks in a wave
I—l
/\ /\
What are wavelengths measured in?
meters
What is the symbol for frequency?
v
What is frequency measured in?
1/seconds or just seconds^-1
What is speed measured in?
meters/seconds
What is a frequency?
number of cycles that pass through a point in space, how many cycles there are in a given time frame
What is the speed in terms of waves?
how fast the waves travel
What is the equation for the speed of light?
c = λv
What is the constant for light?
c = 2.998 x 10^8
What is the highest point in a wave called?
amplitude
The relationship between wavelength and frequency is
inversely related
The longer the wavelength, the ___ the frequency
the longer the wavelength, the lower the frequency
The shorter the wavelength, the ____ the frequency
the shorter the wavelength, the higher the frequency
What is the electromagnetic spectrum?
includes gamma rays, x rays, uv light, visible light, infrared, microwaves, radiowaves (FM AM)
What does AM stand for?
amplitude modulation
What does FM stand for?
frequency modulation
What is interference?
how well two waves are able to communicate with one another
What are the two types of interference?
constructive interference and destructive interference
What is constructive interference?
when two waves are parallel to one another and line up to form a wave with higher amplitude ( creates light spots)
What is destructive interference?
when the trough and peak of two waves are touching, forming a straight line and no light
What is diffraction?
occurs when light is scattered from a regular array of points or lines, each color has different angle reflectee
When does diffraction happen?
when light hits a rough surface
What is the ultraviolet catastrophe?
the thought that objects could have an infinite amount of energy when burned
What did Max Plank observe?
energy can be gained or lost only in multiples of hv (h is plank’s constant). energy exists in certain intervals
What is the change in the energy equation?
delta E= nhv
What is the photoelectric effect?
the phenomenon in which electrons are emitted from the surface of a metal (solid) when a specific frequency or higher than that specific frequency of light strikes it
What are the properties of the photoelectric effect?
1) no electrons are emitted by metals below a specified threshold frequency (v0), regardless of light intensity
2) for light with frequencies greater than the threshold, the number of electrons increases linearly with the intensity of light
3) for light frequencies greater than the threshold, kinetic energy from the electrons get emitted
What are photons?
stream of “particles” of electromagnetic radiation, as light intensity increases the more photons there are in the stream
What is the dual nature of light from de Broglie?
all matter exhibits properties of waves and particles
What is de Broglie’s equation?
λ = h / mv (v is velocity)
What is the continuous spectra?
shining white light through a prism, we can see the colors of light
What are the line spectra?
display discrete wavelengths of light in specific quantities
What did Neils Bohr do?
found radii for orbits of electrons and the equation for energy in a hydrogen atom and difference in energy in energy levels
What did the Bohr level suggest?
electrons can only exist in certain energy levels, an electron’s energy is related to the energy level it occupies
IF the electron moves further from the nucleus, what happens?
energy is absorbed
If the electrons move closer to the nucleus, what happens to the energy?
energy is released
What were the drawbacks of the Bohr Model?
only explained electrons in hydrogen, electrons don’t move in orbitals
What are electron density maps?
the more often an electron occupies a point in space, the darker the space becomes
What are quantum numbers?
the ID of an electron
What are the four quantum numbers?
the principal number, the angular momentum number, the magnetic quantum number, and the electron spin quantum number
What does the principal quantum number determine?
how big of an orbital there is and the distance between the nucleus
What is the principal quantum number?
n = #
What does the angular momentum quantum number determine?
shape of the orbital
What is the angular momentum quantum number?
values of 0 to n-1 represented by l letter
l = 0 is what letter?
s
s = which l number?
0
l = 1 is what letter?
p
p = which l number?
1
l = 2 is what letter?
d
d = which l number?
2
l = 3 is what letter?
f
f = which l number?
3
After l = 3, what happens to count?
going in numerical order and alphabetical order
What does the magnetic quantum number determine?
determines the number of each type of orbital per energy level
What is the magnetic quantum number?
ml
What does the magnetic quantum number consist of?
-l to +l, so if l =3 ml = -3, -2, -1, 0, 1, 2, 3
What is the electron spin number?
-1/2 or +1/2 for electron tilt
What is the pauli exclusion principle?
the principal number and the angular momentum number can never be the same
Orbitals can only have how many electrons?
2
What are orbitals?
regions in space where electrons can be found
What are nodes?
areas with zero probability of finding an electron (gaps, open space)
What does the total number of nodes equal?
n-1
What shape are s-orbitals?
spherical o
What shape are p-orbitals
dumbbell oo
The probability of finding electrons is greatest near…
greatest near the nucleus and decreases exponentially further away
What are degenerate orbitals?
orbitals with the same energy IN HYDROGEN, orbitals with same value for n (ex 3s, 3p, 3d)
What is the Bohr Model equation for a hydrogen atom?
e = -2.178x^-18 J (Z^2/n^2)
What does the Z stand for in the Bohr Model equation for hydrogen?
nuclear charge
l = 4 is what letter?
g
g is what l number?
4
l = 5 is what l letter?
h
5 is what l letter?
h
What are the three things we must consider when there is more than one electron involved?
1) KE of electrons as they move
2) PE of attraction between nucleus and electrons
3) PE of repulsion between two electrons
What is electron screening/shielding?
the negative charge AROUND the nucleus shields the electron of interest from having a stronger bond with the positive nucleus since other electrons are occupying inner energy levels
Can electron shielding be applied to hydrogen atoms?
NO
What is the penetration effect?
the ability of an electron to get close to the nucleus
In the same energy level, what is the strongest PENETRATI?
s then p then d then f
In different energy levels aka principal quantum numbers, what is the strongest penetration power?
distance from the nucleus (the smallest n number)
What did Dimitri Mendeleev discover?
the patterns of the periodic table, possibilities of unknown elements, chemical properties of elements
What does the Aufbau Principle state?
electrons fill the lowest available energy levels (aka orbitals) before occupying higher levels
What is Hund’s Rule?
1) electrons fill degenerate orbitals singly before pairing
2) unpaired electrons have the same spin (point in the same direction)
What are the rules for building orbital diagrams?
1) identify the number of electrons that are supposed to be indicated in the diagram
2) place electrons in the lowest energy first
3) electrons have to face the same way in generate orbitals until being paired up
4) each orbital can contain a max of 2 electrons with opposite spins
How do you remember orbital order?
1s 2s, 2p 3s, 3p, 3d 4s, 4p, 4d, 4f 5s, 5p, 5d, 5f, 5g
What are orbital diagrams?
represents the number of electrons an atom has in each occupied orbitals (has those half arrows and 1s^2 etc symbols)
What are electron configuration diagrams?
represent the distribution of electrons in orbitals (i.e. 1s^2, 2s^2)
How do you write condensed electron configuration?
1) in brackets, write the symbol for the noble gas that comes directly before the element of interest (for example, if in the 4th period (n=4) then go to last column and count from 2 to 4 (aka Argon)
2) write electron configuration for all remaining electrons (amount of electrons atom has - noble gas electrons –> put the last portion of electron configuration diagram that equal to remaining electrons after subtracting)
like Na in 3rd period with 11 electrons 1s^2, 2s^2, 2p^6, 3s^1 —> count 2,3 down to [Ne] on last column has 10 e, so that means 11-10 = 1, to put together [Ne]3s^1 since last portion has 1 electron left like subtracted number)
In the periodic table, where can you find s?
right side (1-2)
In the periodic table, where can you find d?
in the center columns (3-12)
From going from the 1st and 2nd column of the periodic table to the 3-12, the n number
decreases by 1 (4s goes to 3d)
In the periodic table, where can you find p?
right side (13-18)
The exception for the electron configuration and condensed electron configuration is where?
in all elements in the Cr column and all elements in the Cu column (instead of [Ar} 4s^2 3d^4 it is 4s^1 3d^5)
What group(s) is the alkali metals?
group 1A
What group(s) is the alkali earth metals?
group 2A
What group(s) are transition metals in?
3-12
What group(s) are halogens in?
7A aka 17
What group(s) are noble gases in?
8A aka 18
What are valence electrons?
electrons found in the principal quantum level (n) of an atom (ex: 1s^2 2s^2 2p5 means 2s^2 2p^5 are the valence electrons)
What are the core electrons?
all the inner electrons
What does it mean if elements are in the same group in terms of electrons and properties?
elements in the same group have the same number of valence electrons and they behave in a similar manner
Metals want to ____ electrons
metals want to LOSE electrons
Nonmetals want to ___ electrons
nonmetals want to GAIN electrons
Which metals on the periodic table are easy to cut?
group 1A, alkali metals
What is the periodic table trend for the atomic radius from left to right?
from left to right, the atomic radius decreases because the angular momentum number decreases
What is the periodic table trend for the atomic radius from top to bottom?
from top to bottom, the atomic radius increases because the angular momentum number increases
If atoms lose electrons, what are they called?
cations
When atoms lose electrons, what happens to the atoms’ size?
they become smaller because the nucleus pulls harder
If atoms gain electrons, what are they called?
anions
When atoms gain electrons, what happens to the atoms’ size?
they become bigger because
What is the periodic table trend for the ionic size from left to right?
the ionic size increases
What is the periodic table trend for the ionic size from top to bottom?
the ionic size decreases
What are isoelectric ions?
ions with the same number of electrons (ex: F- and Na +)
What does ionization energy refer to (I1, I2 etc..)
the amount of energy needed to remove an electron from an atom or ion
What is the periodic table trend for ionization energy from left to right?
from left to right, it increases
What is the periodic table trend for ionization energy from top to bottom?
from top to bottom, it decreases
What is electronegativity?
the ability of an atom to attract electrons
What is the periodic table trend for electronegativity from left to right?
electronegativity increases from left to right
What is the periodic table trend for electronegativity from top to bottom?
electronegativity decreases from top to bottom
What is the trick for determining how many orbitals are in a certain principal number?
take the n number and square it n^2
Why was the Davisson-Germer experiment significant?
all matter exhibits properties of matter and waves because of the diffraction pattern
What is the Heisenberg uncertainty principle?
limit to how precisely we can describe a particle position and momentum
What did Schrodinger do?
found the areas where electrons would be most likely be present in a HYDROGEN ATOM
