exam 1 Flashcards

Question

Robert Milikan

Answer 1

- discovered what the charge of an electron was - famous oil drop experiment - would shoot x rays to the oil drops and the oil drops would basically float | think milk and oil dont mix so milkman brought the charge

Answer 2

electrons and protons just scattered all throughout, no specific central structure | think jiggly w no structure

Answer 3

in late 1800s, scientists found that some elements produce high-energy radiation 3 types: **gamma rays**: high energy "light" **beta** **particles**: high speed electrons **alpha particle**s: posseses a 2+ charge

Answer 4

- discovered the nucelus - performed experiments to test plum pudding model - dense positively charged core - threw beam of alpha particles at thin metal foil and some of them would go to the middle and just completely shift course | think ruth is the center of my life

Answer 5

1. number of electrons 2. arrangement of electrons

Answer 6

atoms w/ same number of protons and electrons, but different number of neutrons

Answer 7

solids: fixed volume & shape liquids: fixed volume, no fixed shape gases: no fixed volume, no fixed shape

Answer 8

206 Po 84 mass number on top, atomic number on bottom

Answer 9

atomic # = # of protons & electrons mass # - # of protons = # of neutrons

Answer 10

sum of (fractional abundance x mass of isotope)

Answer 11

*fancy word for light* energy that behaves like a wave and travels at the speed of light in a vacuum

Answer 12

2.998 x 10^8 m/s

Answer 13

1. wavelength 2. frequency 3. amplitude 4. speed

Answer 14

the distance between 2 consecutive peaks in a wave | symbol: λ (lambda)

Answer 15

number of cycles per second that pass through a point in space | symbol: ν ## Footnote unit: 1/s or Hz (hertz)

Answer 16

magnitude of the wave's displacement | (the size of the peak of that wave)

Answer 17

how fast the wave travels

Answer 18

volume *the louder the sound, the greater the amplitude*

Answer 19

inversely related - wavelength halves = frequency doubles *only true for light, sound waves don't behave the same*

Answer 20

c = λv c = speed of light λ = wavelength v = frequency

Answer 21

- red are the lowest energy levels (on the right) - higher the frequency, higher the energy - increasing energy and frequency going to the left - increasing wavelength going to the right | that random chart looking thing where it goes from blue to red

Answer 22

2 waves come into contact with each other

Answer 23

- constructive: 2 waves that are IN PHASE (same peaks & troughs) add together result: higher amplitude - destructive: 2 waves that are OUT OF PHASE (perfectly misaligned, their peaks & troughs match up) result: balance out and becomes straight line

Answer 24

waves that remain constrained in a region of space (not moving in space but have oscillations like a guitar string) - **nodes**: spaces along standing waves which are not in motion

Answer 25

waves that are not moving but amplitude keeps changing because of interference

Answer 26

- late 1800s to early 1900s - physics at that time couldn't explain why hot objects didn't give off infinite amount of UV light - led to Planck's theory that energy can only exist in discrete "packets"

Answer 27

*energy is quantized* - energy can be gained or lost only in multiples of hv ΔE = nav ΔE = change in energy for a system n = any integer h = Planck's constant (6.626 x 10^-34 Jxs) v = frequency of electromagnetic radiation

Answer 28

phenomenon in which electrons are emitted from the surface of a metal when light strikes it - explained by Einstein

Answer 29

1. no electrons are emitted by metals below a specific threshold frequency, **regardless of light intensity**! 2. for light with frequencies greater than v0, # of electrons emitted increases with increasing light intensity 3. for light with frequencies greater than v0, the kinetic energy of electrons emitted increases with increasing light frequency *basically saying that intensity (brightness) of light determines the number of photoelectrons, while frequency (color) of light determines energy*

Answer 30

stream of "particles" of electromagnetic radiation - intensity of light is a measure of the # of photons present in the beam (more intense light = more photons) - energy of photons is directly proportional to frequency of light

Answer 31

- shows that energy and mass are related E = hc/λ

Answer 32

**continuous spectra** result when white light passes through a prism (contains all wavelengths of visible light) **line spectra** display discrete wavelengths of light (specific bands showing, not the entire spectrum)

Answer 33

when energy is applied to hydrogen gas, hydrogen molecules (H2) absorb energy and some molecules are split into atoms (H) - electrons are *excited* - electrons don't like staying at high states wanna go lower, energy is released when they go lower

Answer 34

1/λ = -R (1/ (n final)^2 - 1/ (n initial)^2) R = 1.097 x 10^7 1/m

Answer 35

- electrons in hydrogen atoms orbited the nucleus in certain *energy levels* - extended Planck's idea that light can only exist in specific intervals to electrons - an electrons' energy level is related to the energy level it occupies (further or closer to nucleus dictates how much energy it has) *electron moves further from nucleus = energy absorbed* *electron moves closer to nucleus = energy released*

Answer 36

E = -2.179 x 10^-18 J (Z^2/n^2) Z = nuclear charge (+1 for H) n = any integer

Answer 37

1. insufficient for explaining atoms other than Hydrogen 2. in reality, electrons do not move around atomic nuclei in circular orbits (but Bohr spurred quantum mechanics)

Answer 38

n principal level - 2n^2 is the formula to find # of electrons possible ex. n = 2, 2(2)^2 = 8 - if ms is only one number given, half the n value that u found - l = 0 is s orbital - l = 1 is p orbital - l = 2 is f orbital - l = 3 is d orbital *if 4 quantum numbers are given, the answer is always 1 b/c 4 quantum numbers can only specify ONE electron*

Answer 39

every single moving particle (including electron) has a wavelength associated with it λ = h/mv h = planck's constant m = mass v = velocity *if mass is larger, denominator is larger so wavelength is smaller = explains why wavelength of macroscopic objects was not sensed bc the wavelength was too small*

Answer 40

- provided strong evidence that electrons behave as waves - same exact diffraction pattern as waves - finally ended the debate and the physics world acknowledged this

Answer 41

for any particle, can only know the position & momentum with very *limited* precision ∆x x ∆ p (mv) ≥ h/4π (don't need to memorize this equation)

Answer 42

used to find the probability of where the electron exists

Answer 43

gamma rays -> x-ray -> UV -> visible light -> infrared -> microwaves -> radio waves

Answer 44

intensity of color depicts probability value near a given point in space

Answer 45

n = principal quantum number (orbital's size, energy, and distance from the nucleus) l = angular momentum (specifies shape of the orbital) *up to n-1* # of subshells increase as l increases ml = specifies orientation of each orbital in 3D space *-l to +l* ms = electron spin *always +/- 1/2*

Answer 46

areas with zero probability of finding an electron - total number of nodes in an orbital is equal to n-1

Answer 47

no 2 electrons in the same atom can have the same set of 4 quantum numbers! - orbitals can hold a maximum of 2 electrons *like saying 2 people have the same ID number*

Answer 48

denegerate orbitals are orbitals with the same energy in hydrogen, orbitals with the same value for n are degenerate

Answer 49

- as energy level (n) increases, energy of orbital increases - as angular momentum (l) increases, energy of orbital increases too

Answer 50

effect where electron experiences reduction in the effective nuclear charge due to electrons occupying inner energy levels

Answer 51

ability of an electron to get close to the nucleus - the lower in energy level is more penetrating (n takes precedent) ex. 4s and 5p --> 4s e- is more penetrating

Answer 52

electrons fill the lowest available energy levels (orbitals) before occupying higher levels

Answer 53

1) electrons fill degenerate (orbitals that have the same energy) singly before pairing 2) unpaired electrons have the same spin *start with spin facing upwards first* - that diagram looking thing where you draw the half up and down arrows to show electrons -

Answer 54

electron configurations: represent the arrangement of electrons in orbitals of atoms orbital diagrams: picture that shows arrangement

Answer 55

valence: outermost electrons (includes all of them with the same n value) core: all the inner electrons (everything but the valence electrons)

Answer 56

in brackets, write symbol for noble gas that comes directly before element, then write configuration for all remaining electrons

Answer 57

Cr's row and everything in it and Cu's row and everything in it bump one electron from s to d ex. 4s2 5d9 becomes 4s1 5d10

Answer 58

similar properties

Answer 59

half the distance between the nuclei of 2 atoms of an element

Answer 60

- increases down groups *b/c more orbitals so greater in size* - decreases across periods *b/c effective nuclear charge increases, decreasing atomic radius, greater "pull" for electrons*

Answer 61

ions with the same number of electrons

Answer 62

- increases down groups - decreases with effective nuclear charge (for isoelectronic ions)

Answer 63

amount of energy required to remove an electron from an atom to an ion **trend**: - decreases down groups - increases across periods (left to right)

Answer 64

oxygen has 2 electrons in the same orbital which causes repulsions b/c they're both negatively charged particles for that reason, more favorable to remove electrons from oxygen than from nitrogen

Answer 65

ability of an atom to attract electrons **Trend**: - decreases down groups - increases across periods (left to right)

Answer 66

credited for originally organizing the period table managed to: - correct several values for atomic masses - predict properties of later discovered elements (would put question marks n stuff)

exam 1 Flashcards

(90 cards)