Chapter 5: A Closer Look at Matter Flashcards
why is hydrogen so different from other elements?
it has only one electron so there is no electron interation within the atom
which subshell is this?
p
which subshell is this?
s
in the late 17th century, who proposed that elements were any material that a single substance that could not be broken down anymore
Robert Boyle
what do you call the magnetic orientation of an electron?
it’s magnetic moment
what could Thomson conclude about the cathode particles and hydrogen ions?
that they have the same charge and the cathode particles are significantly smaller than H+
if orbitals have the same angular momentum quantum number, they are in the same ______?
subshell
once the air from the Crookes tube was vacuumed out, what happened?
the pink glow faded and the opposite cathode was glowing a vibrant green
who came up with the plum-pudding model
Thomson
what are the two possible values that ms can hold?
ms = -1/2 and ms = 1/2
whose mathematical equation describing frequencies given off by a black body at a given temperature did not work at high temps?
Lord Rayleigh and Sir James Jeans
who proved Einstein’s theory of light behaving like a particle?
Robert Millikan
in a system with a fixed distance, what will happen to the frequency?
the frequency will change to keep the distance fixed
Thomson discovered the cathode ray was always deflected towards the ______ plate
positive
Who thought to think of energy as a particle, rather than as a wave?
Planck
def: the number of neutrons in a nucleus (N)
neutron number
what is the frequency below which the light no longer generates an electric current called?
a threshold frequency
who predicted the neutron?
Rutherford
def: a quantum number that descirbes an electron’s magnetic orientation, created as a result of being a moving charge
spin quantim number (ms)
def: a visual representaiton of an atom’s electron configuration using: boxes or lines for the atomic orbitals, arrows for the electrons and the arrow direction indidcation the spin
orbital diagram
def: a notation that identifies the organization of electrons in an atom, indication the sehll they’re in, the subshell they’re in and how many in that subshell
electron configuration
def: whole number representing the number of protons, the charge of an atom or ion and the number of electrons in a neutral atom (Z)
atomic number
what are the two types of waves?
travelling waves and standing waves
def: a device that separates light into its component wavelengths, allowing the measurement of those wavelenghts
spectroscope
what does AZE notation include?
atomic number, mass number and element
who discovered the neutron?
James Chadwick
what did aristotle propose about matter?
that it’s made of earth, water, air and fire
def: a unique pattern of spectral line given off by each element, representing specific frequencies and wavelengths, and therefore specific energies
bright-line spectrum
who discovered that every element has a different bright-line spectrum?
Niels Bohr
if light is a particle, and quanta are made of particles, increasing the light’s intensity is equivalent to producing ________
more quanta
def: refers to neurtal atoms and charged ions who have the same number of electrons occupying the same orbitals, giving them the same electron configuration
isoelectronic
def: a 3D representation of the square of an electron’s wave function, representing where in space around the nucleus we have the highest probability of finding that electron
atomic orbital
applying a high voltage across the electrodes in a Crookes tube cause what to happen?
the air inside the tube glowed pink
what are the two ways you can change a wave system?
- fixed distance and a variable wavelength - fixes wavelength and a variable distance
is light a wave or a particle?
both
what are the key points of Bohr’s atomic model for hydrogen?
- the hydrogen atoms has a specific allowed energy levels or stationary states 2. as long as electrons are in the allowed energy levels, they do not give off or absorb energy 3. electrons can only move between the allowed energy levels if they absorb or give off the amount of energy needed to go between levels
what did Werner Heisenberg say about subatomic particles?
that you can know their position or momentum but not both
how did Thomson modify the Crooke’s tube?
- employed a better vacuum pump 2. modified the anode, creating a focused cathode ray 3. coated the inside of the glass with phosphorescent compound that lit up when cathode rays struck it 4. added a pair of metal plates between the anode and the end of the tube, creating a controllable electric field
how did Schrödinger treat electrons? waves or particles?
waves
T or F: electrons can’t hold the same ms number
True, only one spin up and one spin down
def: in the same atom, no two electrons can have the same combination of four quantum numbers, n, ℓ, ml, and ms
Pauli exclusion principle
Thomson believed the Crookes tube contained _________, not letting scientists observe any interactions
residual air
the bigger the n value…?
the bigger the orbital, more energy, larger distance from nucleus
def: when multiple orbitals of equal energy are available in a subshell, electrons will fill the orbital’s individually before pairing up
Hund’s rule
which subshells are these?
f
def: a quantum number that determines an orbital’s shape for which we use a corresponding letter to distinguish it form the principal quantum number
angular momentum quantum number (𝓁)
can an element be its own core?
no
J.J. Thomson believed that an _______ would cause the cathode rays to be deflected
electric field
scientist understood that cathode rays are made up of _________
charged particles
what range of values can 𝓁 have?
𝓁 = 0 to 𝓁 = n-1
def: the concept that quantized entities and elementary particles, like light and electrons, display both wave and particle natures, requiring both to properly describe them
wave-particle duality
def: the set of orbitals of the same type, each having the same angular momentum quantum number
electron subshell
what does the energy of a given quantum depend on ?
the oscillators’ speed, the faster the oscillator the more likely to vibrate
def: gas-discharge tube that has two electrode, a negative cathode at on end and a positive anode about halfway down, and a flat cross about two thirds of the way along
Crookes tube
the only way an electron can carry a charge and have a mass is if it’s a _______
particle
what is the difference between the mass number and the atomic mass?
atomic mass is the average of all element’s atoms while mass number describes the composition of a specific atom
T or F: Electrons occupy the specific orbits around the nucleus allow them to form circular standing waves
True
who named beta decay and gamma decay?
Rutherford
T or F: using math, we can tell exactly where electrons will be and what momentum they’ll have
False, we can only know where they are likely to be and how they’re likely to be moving
how did the charge-to-mass ratio that Thomson found compare to that of a hydrogen ion
it was 2000 times bigger
orbitals with the same “n” number are called _______
shells
what are the first four subshells?
s, p, d, f
T or F: electrons can hold the same n, ℓ and ml numbers
True
what were two points of Rutherford’s atomic model?
- the nucleus represented most of the atom’s mass, but little volume 2. the electrons outside the nucleus represented most of the atom’s volume but very little mass
def: a whole number representing the sum of the number of protons and neutrons in the nucleus (A)
mass number
which student of Rutherford believed that the atom had a positively charged nucleus?
Niels Bohr
what were some of Bohr’s points on energy levels and stationary states?
- each energy level is a circular orbit - the further the orbit from the nucleus, the higher the energy - each level has a quantum number, whole number starting at 1 - lowest energy level orbit is the ground state - larger orbits of higher energy are excited states
what offers the best evidence for light as a wave?
diffraction
how can you find the neutron number?
neutron number = mass number - atomic number
def: mysterious agent causing a green glow in the Crookes tube
cathode ray
with the concept of quanta, what was Planck doing to energy?
he was quantizing it
Scientists knew that energy _______________ then _____________
increased to a maximum then decreased as frequency continued to increase
law of classical physics would lead to the electrons __________
losing energy and rapidly spiralling inwards toward the nucleus. making unstable atoms
who legitimized Planck’s Postulate?
Albert Einstein
T or F: low frequency light, no matter it’s intensity does not generate an electric current
True
T or F: quanta are divisible
False, you can only have whole quanta
what did De Broglie’s equation say about particle wavelength?
that wavelength is inversely proportional to the particle’s mass and velocity
who proposed the proton?
Rutherford
T or F: electrons can only take two possible orientations
True
what did Planck call the bundles of energy her proposed?
quanta
what was the name of the disagreement between classical prediction and experimental observation concerning radiation?
the ultraviolet catastrophe
def: electrons tend to full to maximum any orbitals in the lowest available subshell first, before filling a higher-energy orbital
Aufbau principle
T or F: 𝓁 is dependent on n
True
def: an experiment involving an alpha particle source, fluorescent screen and gold foil?
Rutherford gold foil experiments
what did aristotle’s idea of matter lead to?
alchemy
what two predictions in Rutherford’s atomic model were proven false?
- matter should be unstable 2. light given off by atoms should be a continuous spectrum
who discovered alpha decay?
Rutherford
how did Heisenberg treat electrons? waves or particles?
particles
by comparing similar measurements using a magnetic field, Thomson was able to determine the ______ of the cathode-ray particles
charge-to-mass ratio
in a system with a variable distance, what will happen to the frequency?
the frequency will stay the same as the distance changes
what did democritus call the small indivisible particles of matter?
atomos means indivisible
what happened to alpha particles when Rutherford shot them at gold foil?
they were deflected
def: the more precisely you know a particle’s position, the less precisely you can know it’s momentum, and vice versa
Heisenberg’s uncertainty principle
def: a shotened electron configuration that simplifies the reporting of inner core electrons while fully reporting valence electrons
core notation
how do we represent the core electrons in core notation?
using the symbol of the noble gas from the previous row
def: an elementary particle, whose substructure is unknown, representing a quantum electromagnetic radiation
photon
the principal quantum number refers to the ______
electron shell
def: the set of all the orbitals described by the same principal quantum number
electron shell
T or F: in a hydrogen atom, all the orbiatals have different amounts of energy
False, in hydrogen atoms, all orbitals have the same amount of energy
what were the 4 main points of dalton’s atomic theory?
- all matter is composed of tiny particles, which can’t be broken down, created or destroyed 2. atoms of a given element are identical to each other, but different from other elements 3. atoms if different elements combine in specific ratios to form compounds 4. in a chemical reaction, atoms separate or rearrange to form new compounds
“Cathode rays are made up of streams of ________ charged particles who are ______ in size.”
negatively subatomic
Bohr’s model accurately explained and predicted _______________ and was lacking ________
most of hydrogens bright line spectrum, but not all of it and was lacking theoretical basis
def: Bohr’s original quantum number, indicating the orbital’s size and energy relative to other orbitals, and it’s distance from the nucleus
principal quantum number (n)
what did Bohr call the distances in which the electrons orbited the nucleus?
stationary orbits
what is the equation for 𝓁
𝓁 = n-1
def: the study of energy given off by hot objects
black-body radiation
a high frequency quantum has lots of energy, but in an actual system, _________
is less likely to exist
T or F: Bohr thought electrons emitted electromagnetic waves
False
Bohr’s theory behind his math could not explain why some lines on the spectrum where _____ than others
brighter
T or F: ml is related to 𝓁?
True
In 1897, J.J Thomson set about characterizing ________
cathode rays
how many electrons can one orbital hold?
two electrons
1 spin up, 1 spin down
what did the ancient greeks propose about matter?
that solid matter could be cut into smaller and smaller pieces until there was a piece that you could no longer cut up. there is also empty space between matter, in different proportions
what range of values can ml have?
values ranging from -𝓁 to 𝓁, including 0
Thomson could conclude what about cathode rays?
that they are made up of streams of negatively charged particles
which subshells are these?
d
who proposed the nucleus?
Rutherford
def: atoms of a given element that have the same atomic number but different neutron numbers and therefore different mass numbers
isotopes
T or F: the energy levels in hydrogen atoms are simple
True
who provided the theoretical foundation that was missing in Bohr’s model?
de Broglie
def: a quantum number that describes an orbital’s orientation in space, leading to a specific number of orbital’s in each subshell
magnetic quantum number (ml)
