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Gen Chem Ch. 1-3 Midterm
Terms in this set (106)
What are some elements found in nature? (list 5)
Gold, silver, copper, sulfur, and mercury
What was the first controlled reaction? What were the 3 resulting products of that reaction?
Fire; ash, heat, and light
What is bronze made up of?
Copper and tin
What causes iron to turn into iron oxide? Why does iron tend towards iron oxide?
Oxygen exposure; because iron oxide is energetically favorable (has a lower E)
__________ believed that matter could be cut in half infinitely. __________ believed correctly that there is an indivisible piece of matter.
__________ was the belief that earth, wind, fire, and water made up everything.
What is objective, governed by natural laws, and is discoverable?
What is the difference between a law and a theory? Which did Einstein and Newton do relating to gravity?
A law OBSERVES what is happening (such as Newton describing gravity) while a theory EXPLAINS an observation (WHY, HOW) (such as Einstein explaining gravity)
Who decided that phlogiston was released when wood became a tiny pile of ash? What was the big idea?
Boyle; big idea was that there is stuff we can't always see
Who established the Law of Conservation of Mass? How? What does that law imply?
Lavoisier; he measured the mass of mercury oxide before and after it reacted to form mercury and oxygen and it was the same mass; matter is neither created nor destroyed
What does the Law of Definite Proportions imply? How was it established? What is the other name for it?
A substance is always made of the same proportion of elements; discovered when Proust measured the percentage of O and H in differing amounts of water and they were the same; Law of Constant Composition
What does the Law of Multiple Proportions imply? How was this determined?
Elements combine in small, whole # ratios, which suggests small, discrete particles; Dalton examined CO and CO2 and found that if C was kept at a constant mass for both molecules, the O's would have mass ratios in whole numbers.
What is the fourth state of matter?
Difference between mass and weight.
Mass is the amount of matter in an object (always constant) while weight is the force that gravity exerts on matter (changes with gravity)
Symbol and factor of nano
Symbol and factor of micro
Symbol and factor of milli
Symbol and factor of centi
Symbol and factor of deci
Symbol and factor of kilo
Symbol and factor of mega
Symbol and factor of giga
sig fig rules:
1) for adding and subtracting, round to...
2) for multiplying and dividing, round to...
3) if 5 is dropped and nonzero digits follow, round...
4) if 5 is dropped and zero or nothing follows, round...
1) # of decimals of least decimals
2) # of sigfigs of least sigfigs
4) up or down, whichever yields an even value
Dalton's atomic theory:
1) Matter is made up of....
2) An element is made up of... with a specific...
3) Atoms of different elements have different...
4) ______________ have atoms of 2 elements in a ratio
5) Atoms are neither...
Which have been proven untrue?
2) atoms with a specific mass
5) created nor destroyed
2 because isotopes and 5 because radioactivity
What are the three things that Thompson discovered (cathode rays, different elements, mass of particles)? How did he find out the thing about the mass of these particles? What did those three things conclude in? How did he do it?
1) Cathode rays are negatively charged particles, 2) Different elements have the same particles, 3) Mass of particles is small. He found out that the mass was small because F=ma and if e (charge of particle) = F then a=e/m and a equals -1.8E8, so the mass must be very small. Discovery of the electron. He used charged plates that changed the direction of cathode rays to go towards the positive plate.
Millikan discovered that the electric field in his _____ ______ experiment had to be a multiple of __________ C to suspend particles. This effectively determined the charge and mass of the ________. The mass is ________ and was found using what equation?
-1.6E-19; electron; 9.1E-28 g; F=ma --> e=ma --> m=e/a
What are the four things Rutherford discovered (contained, neutral particles, negative charge, positive charge)? How? What discovery did this lead to?
1) + and mass is contained in a small area, 2) neutral particles have mass in the nucleus, 3) - is spread out and is mainly empty space, 4) + and - cancels out. He used the gold foil experiment (Used a ray gun to shoot alpha particles at gold foil. Most went through and some deflected, implying that there is a nucleus).
Charge of the proton in C? Neutron? Electron?
Mass of them in amu? (amu to g is given on exam so you could calculate)
1.6E-19 C, 0, -1.6E-19 C
1.007 amu, 1.009 amu, 0.00055 amu
Carbon-12 = ___ amu
1 amu = ____ Carbon-12
Is the mass of 6 neutrons and 6 electrons is more or less than 12 amu? Why? What is this called?
Mass is larger because keeping the atom together takes energy, and that energy comes from the little extra mass.
Atomic number is...
the number of protons
Mass number is...
# protons and neutrons, estimate of mass
In Carbon-12, what does 12 represent?
The mass number (estimate of mass, protons + neutrons)
Ions have different numbers of ______
Isotopes have different numbers of _____
ions - electons
isotopes - neutrons, which causes different mass
Atomic mass is...
the weighted average of the masses of the isotopes of an element
A molecular formula is... while an empirical formula is
uses the exact number of each atom; the ratio of the atoms of each element
What is Avogadro's Number? Number and description. Symbol. What is Avogadro's Number equal to?
The number of C-12 atoms in 12.0 g (1 amu) of C
The ________ _______ of an element is equal to 1 mol of the element.
What is #protons - #electrons
H2 and O2 are examples of ________ molecules
mass of a substance/molar mass =
molar mass =... (in what units?)
What are the units of molar mass?
moles of substance
atomic mass in amu
If the atomic mass of an element is 39.9 amu, which isotope of (36)A, (38)A, and (40)A is most abundant?
(40) A because it's closest to 39.9 amu
The periodic table is...
Wave length is...
Give symbols and units
Number of wave cycles in a specific time (curvy v) (1/s or Hz)
Distance between peaks of waves (λ) (m)
Intensity/height of a wave
What is the relationship of frequency and wavelength as related to the speed of light (c)? Where does frequency come into play?
λv=C; C is constant so as wavelength increases, frequency decreases (inversely proportioned); independent of amplitude
Energy is _____ proportioned to λ and _____ proportioned to v.
As R --> V in ROYGBIV, energy...
increases (think of fire being red before blue)
How do we know that light is wavelike? (what experiment?)
Because of the Double-Slit experiment showing that if electrons go through two slits, they will make a wave-like pattern rather than just two marks. Destructive and constructive interference is made
How does energy determine what we see?
When energy is excited it goes from a ground state to an excited state, and when the energy is released, wavelengths travel. The change in energy determines what we see.
Each λ corresponds to a specific amount of ____.
_____ gases have isolated atoms and so not show full spectrum when excited.
Hydrogen gas exist at specific energy levels. This means that it is ________. All matter is.
What did the photoelectric effect show? How did it do this?
Light is made up of particles called photons. When a certain amount of light E hits lithium, an electron is released. An electron will not be ejected with BRIGHTER light (increased amplitude), only with more E.
E of a photon =
hν or hc/λ (h will be given)
What is the name of h?
What is the work function?
the E of a photon necessary to remove an electron from a metal via the photoelectric effect (photons)
What did Rydberg do? What is the other form of the equation?
mathematically modeled the idea that quantized energy levels of hydrogen would correspond to an energy that would produce these wavelengths of light.
1/λ = R(sub infinity)((1/n^2)-(1/n^2))
This equation and R(infinity) are given on exam
1/λ is subbed for change in E and R is subbed for k (given)
Issues with the Bohr model?
Only works for 1 electron atoms and treats electrons classically (not as predictions)
In λ = h/(mc) for matter, one of the variables is swapped with a different one. Which and why?
λ = h/(mv) because matter cannot have velocity of light.
The wavelength of an electron is ______ then the wavelength of a fastball at 100mph. It is even bigger than an ____. Therefore, microscopic particles are best considered to be ____.
GREATER; atom; waves
The velocity of an electron is ____-like
The position of an electron is ____-like
The Uncertainty Principle states that...
As the _______ certainty increases, the certainty of the _____ decreases
it is impossible to know the exact position and momentum of a microscopic particle.
position, momentum --> also goes for energy and timeWh
What type of wave is an electron? What is a node?
A standing wave, which means that it doesn't travel.
Nodes are where there is no motion in a wave (amplitude = 0)
Wave function squared describes...
the likelihood of finding an electron at a specific point in space (probability density map)
When electrons jump between energy levels, _____ is emitted or absorbed. Which occurs going up vs. down?
going up = absorb, going down = emit
What is an atomic orbital?
Where electrons are likely to be found for each possible quantum state
What are the four quantum numbers? What do each of them describe? What are their symbols?
1) Principle Quantum Number; distance from nucleus (size of orbital), shells; (n)
2) Angular Momentum Quantum Number; orbital's shape; (l)
3) Magnetic Quantum Number; number of orbitals in each subshell (orientation); (Ml)
4) Spin Quantum Number; electrons in an orbital; (Ms)
higher n = ______ energy
n corresponds with ____ on the periodic table
n starts at _ while l starts at _
n is always ___ than l
if n is 3, l can be...
what are the corresponding subshells with each level of l?
0, 1, or 2
s=0, p=1, d=2, f=3
the change in sign on angular momentum quantum number graphs and diagrams is where there is a ____.
There is a __% likelihood that an electron is found within the shape of a subshell.
The total number of nodes is...
The radial nodes are equal to...
The planar nodes are equal to...
How many of each type of node are in a 5f orbital?
total = n-1 = 5-1 = 4
angular = l = 3
radial = n-1-l = 1
If l=0, how many orbitals are there? l=1, 2, and 3?
1, 3, 5, 7
Pauli Exclusion Principle
No two electrons in one atom can have an identical set of Quantum Numbers --> Spin Quantum Numbers diversify
If Ml = 2, what can be said of l?
l is greater or equal to 2 because Ml falls into l categories of l=2, 3, 4, etc, but not lower
An n=3 shell has __ subshells, __ orbitals, and __ electrons
3 subshells, 9 orbitals, and 18 electrons
Electrons in a ground state atom occupy the lowest E orbitals available to them
What is shielding? What is Zeff? How is Zeff affected by shielding? How does this explain why 3d has a higher energy than 4s?
- When electrons in inner shells weaken the attraction between electrons in the outer shell.
- Zeff is the nuclear charge that outer electrons feel.
- Zeff is lowered when there is more interference by shielding electrons.
- Explanation anyone?
When you move higher in E through subshells, the shielding ______, making the Zeff ______.
What is the electron configuration of Silicon using noble gas shorthand (refer to Ptable). Which part is the inner electrons? Which are the outer electrons? What is the name for outer electrons? What do they determine?
[Ne] 2s^2 2p^2
[Ne] is inner and the rest are outer
They determine reactivity
What is Hund's Rule?
Degenerate (equate E) orbitals are single-filled before they are fully filled
Why is the periodic table periodic?
Because each column has the same # of valence electrons; repeating pattern
What are the d block anomalies? What is the main idea for why this happens?
1) d-orbitals are stable when half-filled and fully filled, so 1s electrons can be moved to d-orbitals
2) when losing electrons, d-block elements lose both valence shell s electrons before losing d-block ones
d has lower energy than s-block in d-block IONS
What does it mean if atoms or ions are isoelectronic?
They have identical electron configurations, such as Li^+ and He
How can you approximate Zeff? What is this rule called?
subtracting the charge of the inner electrons from the protons (for estimate)
Zeff = Zact - S
(where S = (0.85 x inner e's)-(0.35 x (valence e's - 1)))
Does a 1s electron in Be have a larger or smaller Zeff than 1s e in Li? Why?
larger because Be and Li have the same number of inner electrons but Be has a larger atomic number, so there is a larger Zeff because of more protons.
Increase of shielding electrons = __________ (descrease/increase) in Zeff. That said, will a 2s electron experience a lower or higher Zeff than a 1s electron?
2s will experience LOWER Zeff
What electron block is best at shielding?
s because they are closest to the nucleus!
An electron is added to 2s before 1s. Which principle is violated?
The Aufbau principle, that states that electrons in a ground state atom occupy the lowest E orbitals available to them
2 electrons are added to a 2px while 2py is empty. Which principle is violated?
Hund's Rule, which states that degenerate (equal E) orbitals are single-filled before they are fully filled
As n (period) increases, Zeff ________ because...
Zeff increases because Z is greater and greater and the effect of electron shielding is not strong enough to make a big difference in most cases.
As Z (atomic number, group) increases, Zeff _______ because...
increases because the inner electrons, which perform most of the shielding, stay constant while the number of protons increases, which creates a more and more positive effect.
Radius of an atom = ______/______
As n (period) increases, atomic radius _______ because....
Radius increases because outer electrons are in larger and larger orbitals, which gives them a higher chance or being farther from the nucleus.
As Z (atomic number, group) increases, atomic radius _______ because...
Radius decreases because the Zeff increases, meaning that there is a higher positive feeling, which pulls the electrons closer to the positive nucleus, making the radius smaller
As an ion of one element becomes more and more positive, the radius _______, because
Radius decreases because there are fewer electrons with the same number of protons, which creates a higher Zeff, pulling the electrons towards the nucleus even more.
As an ion of one element becomes more and more negative, the radius _______, because
Radius increases because there are more and more electrons being added while the protons stay consistent, which increases shielding and makes a lower Zeff. This causes the electrons to be loosened from the nucleus.
What is ionization energy?
The energy required to remove an electron from an atom
What formula is used to calculate ionization energy?
change in E = k((1/n1^2)-(1/n2^2) where k is given
As n (period) increases, ionization energy _______ because because....
IE decreases because when electrons are further away from the nucleus when n increases, it will be easier to pull an electron away. Less energy is required to pull electrons away that are in higher orbitals.
As Z (atomic number, group) increases, the ionization energy _______ because...
IE increases because since the atomic radius is decreasing due to higher Zeff, the electrons are closer to the nucleus and it will take more energy to pull them away.
If more and more electrons are removed, will it be harder or easier to remove them? Where will it be hardest to remove an electron?
Hardest to remove an electron from a noble gas because they are stable and happy that way
What is electron affinity?
The energy released when an electron is added to an atom
As Z (atomic number, group) increases, electron affinity _______ because...
EA increases because ???
Cl^-, K^+, and Ca^2+ are all isoelectronic and have an electron configuration of [Ar]. Which has the largest atomic radius? Which has the smallest)
Cl^- has the largest radius because it has the least protons, which makes it have the lowest Zeff, which means that the radius is the smallest. Ca^2+ has the most protons, which means it has the highest Zeff and therefore the smallest radius.
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