Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

CHEM 101 > Unit 1: Atoms > Flashcards

Unit 1: Atoms Flashcards

(87 cards)

Start Studying
1
Q

What is conservation of mass?

A

atoms (or mass) cannot be created nor destroyed

total mass in a chemical reaction remains unchanged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is meant by constant composition?

A

compounds result from a combination of a specific ratio of different elements
example: CCl4 will always have 1 carbon and 4 chlorine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is meant by multiple proportions?

A

two or more elements combine together to form several different compounds
example: H and O can form H2O or H2O2 depending on how many atoms are present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What experiments showed that atoms are made up of smaller particles?

A

J.J. Thomson’s cathode ray experiment

Millikan’s oil drop experiment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a nucleus?

A

very dense
contains a small positive charge
protons + neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is electron density (electron cloud)?

A

very light
form bonds
responsible for chemistry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are isotopes?

A

atoms of a given element can have different masses due to different number of neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens when an atom has a different number of protons?

A

different elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens when an atom has a different number of electrons?

A

ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is quantum theory and atomic structure?

A

periodic properties of the elements come from atomic structure
Rutherford’s nuclear model is inadequate
our current model is based on quantum theory, which arose out of experiments on the nature of light and matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is matter?

A

particulate (comes in chunks)

travels on definite paths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is energy?

A

continuous

spreads out in all directions “wave-like”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is frequency?

A

cycles per second

units of s^-1 or Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is wavelength?

A

the distance a wave travels in one cycle

units of length (m, nm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is amplitude?

A

the height of a wave crest or depth of a trough

maximum displacement of the wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is refraction?

A

bending of waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is diffraction?

A

interference of waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What experiments showed that light also has particulate properties?

A

Blackbody Radiation
Photoelectric Effect
Atomic Spectra

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is Blackbody Radiation?

A

a solid object emits visible light when it is heated to about 1000K
EM radiation emerging from a blackbody gives a spectrum that cannot be explained by treating light as a wave
higher temperature = higher intensity of light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the Photoelectric Effect?

A

when monochromatic light shines on a metal surface, electrons are ejected
E = hc/wavelength
number of electrons emitted is dependent on the intensity of the light
minimum frequency of light needs to be reached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is Atomic Spectra?

A

when atoms of a vaporized element absorb energy (such as in an electrical discharge tube), they emit light to give a discontinuous line spectrum
spectral lines are produced when an electron moves from one energy level to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Bohr’s Model of the hydrogen atom?

A

the electron can only occupy certain stationary states, with fixed energies
the electron does not lose energy (in the form of radiation) while in a stationary state
the electron undergoes a transition from one stationary state to another by absorbing or emitting photons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the absorption of an electron?

A

excitation from a lower allowed energy level to a higher allowed energy level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the emission of an electron?

A

relaxation from a higher allowed energy level to a lower allowed energy level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is wave-particle duality?
both matter and energy can exhibit both particle and wave-like behavior
26
What is the wavelength of the H atom?
Schrodinger (1927) developed a theory called quantum or wave mechanics to describe particles (such as electrons) as waves
27
What are the different ways to depict the probability of finding the electron in a H atom?
electron density: snapshots at different times, further away from the nucleus less likely to have an electron, r never reaches 0 radical probability distribution: count the dots in each section/sample boundary surface: enclosure of 90% electron density
28
What is the principal quantum number?
symbol: n allowed values: 1, 2, 3, … interpretation: govern the energy and size
29
What is the angular momentum quantum number?
symbol: l allowed values: 0, …, n - 1 interpretation: indicates shape
30
What is the magnetic quantum number?
symbol: ml allowed values: -l, ..., +l interpretation: governs orientation
31
What are the different shapes of hydrogen orbitals?
``` s orbitals (l = 0) are spherical p orbitals (l = 1) are dumbbell shaped d orbitals (l = 2) are clover shaped ```
32
What are many-electron atoms?
in atoms containing more than one electron (many-electron species), the presence of electron repulsion causes the energy of the orbitals to vary in a complicated way
33
How do orbital energies differ in one vs. many electron atoms?
in one electron atoms the orbitals all have the same amount of energy in many electron atoms the orbitals don't have the same amount of energy
34
What factors affect orbital energy?
1. Effect of nuclear charge 2. Effect of electron-electron repulsions 3. Effect of orbital shape 4. A fourth quantum number
35
How does the nuclear charge effect orbital energy?
greater nuclear charge lowers orbital energy
36
How does electron-electron repulsions effect orbital energy?
electron-electron repulsions increase orbital energy | electrons in outer orbitals (higher n) are shielded from the full nuclear charge, so they have higher energy
37
How does orbital shape effect orbital energy?
orbitals with good penetration (having electron density close to the nucleus) have lower energy
38
What is the fourth quantum number?
spin symbol: ms allowed values: +1/2, -1/2 interpretation: spin up or spin down
39
How do you determine electron configurations?
1. Add electrons successively into lowest energy orbitals upward 2. Observe Pauli Exclusion Principle 3. Observe Hund's Rule
40
What is the Pauli Exclusion Principle?
states that "no two electrons can have all four quantum numbers alike" each orbital can be occupied by a maximum of two electrons of opposing spin
41
What is Hund's Rule?
when orbitals of equal energy are available, maximize unpaired spins
42
What trends do electron configurations for transition metal ions follow?
tend to lose valence electrons to form cations | transition metal atoms can form several cations, with the ns electrons being removed before the (n-1)d electrons
43
What does paramagnetic mean?
attracted to an external magnetic field | contains unpaired electrons
44
What does diamagnetic mean?
weakly repelled by magnetic field | all electrons are paired
45
How do we define the size of an atom?
atomic radius = 1/2 distance between two nuclei
46
How do we compare ionic radii?
cations are smaller than atoms | anions are larger than atoms
47
What is ionization energy?
the energy that must be added to remove an electron from an isolated gaseous atom or ion
48
What is electron affinity?
the energy change that occurs when a gaseous atom or ion gains an electron
49
What are the trends of properties down a group?
effective nuclear charge is constant radius increases ionization energy decreases electron affinity becomes less negative
50
What are the trends of properties across a period?
effective nuclear charge increases radius decreases ionization energy increases electron affinity becomes more negative
51
What are properties of metals?
have low ionization energy and less negative electron affinity tend to lose electrons readily
52
What are properties of nonmetals?
have high ionization energy and more negative electron affinity tend to gain electrons
53
What happens to the reducing agent in a redox reaction?
loses electrons is oxidized by the oxidizing agent oxidation number increases
54
What happens to the oxidizing agent in a redox reaction?
gains electrons is reduced by the reducing agent oxidation number decreases
55
Are alkali metals good oxidizing or reducing agents?
good reducing agents because they easily lose electrons
56
Are halogens good oxidizing or reducing agents?
good oxidizing agents because they easily gain electrons
57
What are characteristics of good reducing agents?
easily lose electrons | are in an "unusually low" oxidation state
58
What are characteristics of good oxidizing agents?
easily gain electrons | are in an "unusually high" oxidation state
59
What is the behavior of oxides in water?
metal oxides give basic solutions | nonmetal oxides give acidic solutions
60
What are the best uses of hydrogen for fuel?
1. Haber process: cheapest method to produce ammonia 2. Hydrogenation reactions: unsaturated to saturated 3. An alternative fuel to hydrocarbons
61
What are the advantages to using hydrogen as a fuel?
cleaner (no CO2 produced) | on a per gram basis combustion of H2 releases more energy
62
What are the disadvantages to using hydrogen as a fuel?
no cheap source of hydrogen | difficult to transport and store H2
63
What do each of the letters mean in the A, Z, X notation?
A is on top and it’s the atomic mass number Z is on the bottom and it’s the number of protons X is the element symbol
64
How do you calculate the natural abundance of isotopes?
Let one percentage equal x and the other equal (1 - x) Then use the formula: atomic mass of atom = atomic mass of isotope(x) + atomic mass of isotope(1 - x)
65
What is the name of the polyatomic ion ClO4?
Perchlorate
66
What is the name of the polyatomic ion IO?
Hypoiodite
67
What is the name of the polyatomic ion Cr2O7?
Dichromate
68
What is the name of the polyatomic ion CH3COOH?
Acetate
69
What is the name of the polyatomic ion PO3?
Phosphite
70
What is the name of the polyatomic ion NH4?
Ammonium
71
What is the name of the polyatomic ion HCO3?
Bicarbonate
72
What is the name of the polyatomic ion CN?
Cyanide
73
What is the name of the polyatomic ion HSO4?
Hydrogen sulfate
74
What is the name of the polyatomic ion NO3?
Nitrate
75
What is the name of the polyatomic ion NO2?
Nitrite
76
What is the name of the polyatomic ion MnO4?
Permanganate
77
What is the name of the polyatomic ion CO3?
Carbonate
78
What is the name of the polyatomic ion CrO4?
Chromate
79
What is the name of the polyatomic ion HPO4?
Hydrogen phosphate
80
What is the name of the polyatomic ion SO4?
Sulfate
81
What is the name of the polyatomic ion SO3?
Sulfite
82
What is the name of the polyatomic ion S2O3?
Thiosulfate
83
What are two formulas associated with energy, wavelength, and frequency?
E = hc/wavelength f = c/wavelength
84
What is the relationship between energy and wavelength?
Longer wavelength corresponds to smaller energy
85
What is the definition of shielding?
Refers to the effect that other electrons, especially the inner-shell electrons, have in reducing the full nuclear charge actually felt by an outer-shell electron
86
What is the definition of effective nuclear charge?
The net positive charge acting on a particular atom It’s value is the charge on the nucleus, reduced to the extent that other electrons screen the particular electron from the nucleus
87
What is penetration?
Refers to the occurrence of a probability distribution such that an electron can be found close to the nucleus part of the time, it’s effect is to counteract the shielding of inner electrons so that the orbital experiences a greater than expected effective nuclear charge and is thereby stabilized

CHEM 101 (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions