Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chem 101 > Unit #1 > Flashcards

Unit #1 Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Chemistry flashcards Psychology 101 flashcards Periodic Table flashcards Chemistry 101 flashcards Biology 101 flashcards Organic Chemistry 101 flashcards Sociology 101 flashcards
1
Q

daltons atomic theory

A

matter consists of indivisible and indestructive atoms. atoms of a given element are identical and you cannot convert an elements atom to another

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

what are daltons mass laws (3)

A

conservation of mass: total mass remains constant in a chemical reaction
constant (definite) composition: no matter the source, all compounds consists of the same mass fraction
multiple proportions: in different compounds of the same element, the masses of the combining element can be expressed in simple ratios

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

an atom is:

A

mostly space occupied by electrons, in the center is a tiny region, the nucleus that contains all the positive charge and essentially all of the mass of the atom

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

what is the atomic notation

A

large X with A up and Z down
X - atomic symbol
A - mass number = p+ and n˚ (integer)
Z - atomic number = p+

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

what are isotopes

A

naturally occurring samples of elements may consist of several. they have the same number of protons and electrons, but have a different number of neutrons, this leads to a different mass number

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

equation for (average) atomic mass

A

atomic mass= ∑mx or ∑(isotope mass)(fractional abundance)

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

how do you name ionic compounds

A
  • name the cation first, then the anion
  • add -ide to the name of the anion
  • for metals that can form more than one ion, specify charge by Roman numerals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are polyatomic ions

A

consists of 2 or more atoms joined by covalent bonds and exists as a charged unit (bond ionically)

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

what is the naming schemes for oxyanions

A
  • for families with two oxyanions, the ion with more O’s will end in -ate (may have per- prefix), while the ion with fewer O’s would have an -ite ending
  • for families with four oxyanions (halogens bonded to O), namin scheme: per-…-ate, -ate, -ite, hypo-…-ite (goes as # of O’s decrease)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how do you name covalent compounds

A

nonmetals are bonded to nonmetals
- written in order of increasing electronegativity
- add -ide to the name of the second element
- add numerical prefixes where necessary

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

how do you name acids

A

binary acids contain no oxygen: hydro-…-ic acid
oxyacids: HOX) - name depends on oxoanion:
hypo-…-ite -> hypo-…-ous acid
…-ite -> …ous acid
…-ate -> …ic acid
per-…-ate -> per-…-ic acid

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

what is electromagnetic radiation

A
  • consists of waves, is a spectrum in which frequency and wavelength differs (all travel at speed of light in vacuum). the differing of frequency and wavelengths equates to each part of the spectrum having a different energy
  • a wave is characterized by its amplitude, proportional to intensity, concentration, wavelength, and frequency
    • amplitude is related to the intensity of the radiation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the photoelectric effect

A

when monochromatic light shines on a metal surface, electrons are ejected. each atom changes its energy by an amount of ∆Eatom when it absorbs or emits one photon whose energy is related to its frequency and wavelength (E=hv=hc/λ)

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

explain threshold frequency and absence of a time lag based on photoelectric effect principles

A

tf: an electron breaks free when it absorbs a photon of enough energy; it cannot break free by ‘saving up energy’
aotl: the current is weak in dim light because fewer photons of enough energy are free fewer electrons per unit time, but some current flows as soon as there is sufficient energy

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

what is the equation for electrons that occupy stationary states and electrons in transition between states

A

only for one electron species
- occupy: En=-R(Z^2)(1/n^2)
- transition: ∆E=-R(Z^2)(1/nf^2-1/ni^2)

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

what are the stipulations of the bohr model (3)

A

1) the electron occupies stationary states
2) the electron does not lose energy while in a stationary state
3) the electron undergoes a transition from one stationary state to another by absorbing or emitting photos (Abs: ∆E = + / Emi: ∆E = -)

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

what are the limitations of the bohr model

A
  • it fails to predict the spectrum of any other atoms (other than 1 electron)
  • fails completely for atoms with more than one electron becasue the e- - e- repulsions, nucleus-e- attractions are unaccounted for
  • fails to explain why some emission lines are brighter than others
  • electrons do not move in fixed, defined orbits

this results in wave-particle duality theory

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

what is wave-particle duality

A

removing the distinction between mater and energy:
- proposed matter is wavelike (then e- would have frequencies and energies)

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

how are electrons waves

A

evidence fort he wavelike properties of matter came from observation of diffraction patterns of electrons
- electrons would then have diffraction and interference

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

what is de Broglie’s equation

A

if electrons have properties of energy, do photos have properties of matter? λ=h/mc=h/p aka p=h/λ

  • therefore decrease in momentum of a photon should appear as an increase in it’s wavelength
21
Q

what is the uncertainty principle

A

it is not possible to know both the position and momentum of a moving particle at the same time
∆x∆p ≥ h/4π
- the more accurately we know the speed, the less accurately we know the position and vice versa (we specify the probability of finding an electron somewhere in sapce instead)

22
Q

what is Ψ

A

it is a mathematical description of the elctrons matter-wave in #D
- Ψ^2 is directly proportional to the probability of finding the electron @ a particular point (related w/ quantum numbers)

23
Q

what is schrödinger’s equation

A

it yields the energy state associated with a given orbital

24
Q

what is probability density

A

Ψ^2 is a measure of the probability of finding the electron in some timy volume of the atom. it decreases with distance from the nucleus along a line

25
Q

what are the stipulations of probability density (5 (2 are combined))

A

1) electron cloud depiction - the greater the density of dots, the higher the probability of finding the electrons in that volume (imaginary picture of the e- changing its position)
2) the probability of the electron being far from the nucleus is very small, but never zero (can be an infinite distance)
3 & 4) radial probability distribution: represents the total probability density at some distance r from the nucleus
5) probability contour - the shape that defines the volume around the nucleus (within which the electron spends a given % of time)

26
Q

describe the s orbitals of hydrogen

A

the different ways of representing an orbital: as Ψ or Ψ^2, as electron density, as a boundary surface, or as a radial probability distribution
Ψ - negative exponential graph for 1s almost, the higher the orbital number, the number of cross over’s that exist of the x axis, cross overs are known as nodes
Ψ^2 - nodes drop to y=o. near the nucleus, the volume of each layer increases faster than it’s density decreases. the result is that the probability density pears near (not at) the nucleus

  • # of peaks = n - L, peak intensity increases with each additional peak
27
Q

what is quantum numbers and what are the 3 main ones

A

the state of an electron in an atom is specified by it
a wavefunciton corresponding to a set of the first three quantum numbers is referred to as the atomic orbital
1) prinicpal - n, any +ve integer (≠ 0), interprets orbital size
2) angular momentum - L, 0 to n - 1, interprets orbital shape
3) magnetic, ml, -L to +L, interprets orbital’s spatial orientation

28
Q

what is the relation between the total number of possible ml values and n

A

the total number of ml values for a given n value =n^2 = the total number of orbitals in that energy level

29
Q

true or false: there is a exact relationship between a particular axis and a given ml value

A

f, there is not a exact relationship between a particular axis and a given ml value, … however, we typically associate the ml = 0 to the orbitals whose lobes lie on the z axis

30
Q

what do orbital shapes represent and what do the different orbitals represent

A

they represent the volume in which there is 90% probability of finding the electron
s orbitals: are spherical
p orbitals: nucleus lies at the nodal plane of this dumbbell shaped orbital (lobes lie alone axis described)
d orbitals: describe where nodal planes are, lobes are in between (usually flower shape, except for dz^2 which is like an inverted rolling pin)

31
Q

what are the different plane calculations

A

2 types w/i a atom:
radial: occur where the radial wavefunction equals zero or changes sign (# = n- l -1)
angular: typically flat plane, the number of angular nodes are given by l
total: # = n - 1

32
Q

what the fourth quantum number

A

spin quantum number, ms, describes the spin of electrons (associated w electrons, not the orbitals)
- half of the electrons are attracted by the large external magnetic field, while the other half are repelled by it
- electrons w/ same spin are parallel spin, different spins are opposing sping

33
Q

what is pauli’s exclusion principle

A

no two electrons can have all four quantum numbers alike, effectively, each orbital can be occupies by a maximum of 2 electrons of opposing spins

34
Q

when do we have to make approximations for repulsive forces

A

for many-electron atoms because of the electron-electron repulsions cause the energy of the orbitals to vary in a complicated way

  • in many-electron species, the outermost electron feels attraction from the positive nucleus but also repulsions from other electrons (shielding/screening them)
35
Q

what is effect of nuclear charge

A

the higher the nuclear charge, the greater the pull on the electron. energy is lowered (mote the negative scale and that the system is more stable)

36
Q

what is shielding

A
  • inner electrons prevent the outer electrons from experiencing the full attraction of the nucleus making their removal somewhat easier than expected (blocking the full effect of the nucleu)
  • shielding reduces the full nuclear charge to effective nuclear charge (the nuclear charge electrons actually feel)
37
Q

what is penetration

A

how well the outer electrons are shielded from the nucleus by the core electrons

38
Q

what factors does orbital energy depend on (4)

A

1) greater nuclear charge, lower orbital energy
2) electron-electron repulsions increase orbital energy
3) electrons in outer orbitals (higher n) are shielded from the full nuclear charge, so they have higher energy
4) orbitals with good penetration (having closer electron density) have lower energy

*the inner electrons shield outer electrons better than electrons in the same orbital

39
Q

what is the difference between 2s and 2p in their radial probability distribution and which lies in lower energy

A

2s orbital is more penetration than 2p therefore it lies in lower energy
- s electrons can penetrate and get closer to the nucleus “better” than the p or d electrons. in turn, s electrons will shield or screen outer electrons very effectively
- a 2s e- can penetrate further towards the nucleus and spends part of its time penetrating very close to the nucleus

40
Q

what is the general trend of energy for orbitals in the same shell

A

(more shielding and penetrating, lower energy) s < p < d < f (less shielding and penetrating, higher energy)

41
Q

what is hund’s rule

A

when orbitals of equal energy are available, maximize unpaired spins

42
Q

in what order do you lose electrons

A

p first, then s, then d

43
Q

how is magnetic behaviour related to electron configuration

A

substances can be identified as paramagnetic (contains unpaired e-s, interacts w/ magnetic fields) and diamagnetic (all electrons are paired, does not interact w/ magnetic fields)

44
Q

what are the trends w/ ionic radii

A
  • cations are smaller than atoms, so as Zeff increases there is a net positive charge which shrinks the radius.
  • anions are larger than atoms, Zeff decreases as there is a net negative charge increasing the radius
  • down a group, ionic size increases (b/c n increases)
  • across a period, atomic radius decreases
  • across a period, anion and cation size decreases w/ increasing charge
45
Q

how do we define the size of an atom

A

define it by the extend of the spherical contour (where electrons spend 90% of their time) w/i the atom
- metallic radius: 1/2 the shortest distance b/w nuclei of adjacent atoms
- covalent radius: 1/2 the shortest distance between nuclei of bonded atoms.

46
Q

what is ionization energy and what is its periodic trends

A

the energy that must be added to remove and electron from an isolated gaseous atom or ion
- each successive ionization generally requires more energy
- Zeff increases each time an electron is removed. recall that # of protons does not change but the # of electrons decreases as cations are formed, therefore, more energy is required to remove electrons (held more tightly)
- across a period, IE increases
- down a group, IE decreases

47
Q

what are anomalies of IE

A

electrons tend to want to have a filled or half filled subshell as they are inherently more stable, therefore making their electrons harder to remove, as well species around them want to become more stable, so IE are lower around them

48
Q

what is electron affinity and what is its periodic trends

A

it is the energy change that occurs when a gaseous atom or ion gains an electron (atom to ion)(g)
- across a period, IE increases (usually)
- down a group, IE decreases (as in becomes less negative)
- EA1 is negative (exo, most cases) as the first electron is attracted by the atom’s nucleus
- EA2 is always positive (endo) energy is absorbed (needed) to overcome electrostatic repulsions as additional electrons are added
* Zeff and atomic size affect EA, therefore trends are irregular

Chem 101 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions