Atomic and Nuclear Structure

Question 1

Photoelectric effect 1

Answer 1

light is a particle and a wave, e= Hf

2. e- can only absorb [ackets of one at a time
3. when think abotu kcicking electrons off a minimum amoutn of energy needed to remove an electron the toll anaology is very helpfuL* either the work function or binding energy or the ionization energy the energy per atom or per electrons that is puer mole** so basically what is happening here idea is that hte photos need to have neough energy to pay the toll

Question 2

Below the threshold frequency

Answer 2

Not eneough enegy in photon, cannot cross bridge

Doesnt matter how many ppl show up to bridge with 10 dollar bills, if toll is 16 dollars none of hte electrons get to cross and get ejected* cannot add it up together so cannot pool their money can only pull one electron at a time

if not enpugh energy in the photon it will not happen!

idea at low frequencies we have low energy of photos ppl are showing up with not very much money*

Question 3

At the threshold…..

Answer 3

At the threshold, we are showing up with exactly the right amount of money. we have exaactly what we need to eject the electron no extra!

Question 4

Above the threshold

Answer 4

conservation of energy! where does the extra money go! so if I show up with 20 dollars and spend 16 on teh toll to get over the bridge, then I have four dollars left over. That 4 dollars needs to go to gas money to making me go faster

it goes to the Ke*

This means because extra energy of each photon goes to KE, as inc frequencies of photons above the threshold we are inc the energies of the photon so therefore there is more extra money left over! 20 dolalrs I have 4, 30 dollars I have 14 more money left over so go faster and faster

inc frequency o flight inc the energy of he photons and inc hte Ke of the ejected electrons** however increasing the intensity dodesnt change how much energy is in each photon**

Question 5

In terms of intensity…..

Answer 5

just like traffic! should not change how much money ppl show up with, each ppl still show up with the same amount so therefore always the same amount of extra they should all be going the same speed. The only thing that changes then is the number of electrons ejected, if I have more people show up with this amount of energy I will have more people go across the bridge!

Inc intensity the just changes how many people sho wup

inc freqnecies changes energy of each photon, increases the speed! the KE of hte electrons coming off! inc the intensity just changes hte number of photons showing up the number of electrons beingn ejected!!!

Question 6

1 ev=

Answer 6

1.6 x 10^-19 J

eV is a very small unit of energy

Question 7

alpha decay

Answer 7

the name of decay is what is emitted

“…” decay means named particle that is emitted

Question 8

Beta Decay

Answer 8

beta decay, emitting beta particle, emitting an electron

what is happening in beta decay you are converting a neutron to aproton*** start out with 8n and 6 p end with 7n and 7p so taking something that was neutral and splitting it i nto a positive portion adn negative portion leaving behind a proton where you had a neutron*

Question 9

Beta + Decay

Answer 9

positron decay

converting a proton into a neutron

condensing positive to tiny little thing I shoot out and get rid off and I am left with more neutrons

Question 10

gamma decay

Answer 10

high energy arrangement of protons and neutrons in nuc they rearrange themselves and when they do that they emit a gamma particle*

Question 11

electron capture

Answer 11

Electron capture, not adecay where electron was absorbed notice this here we have 3N and 4 p this is basically neutralizing a proton to turn it into a neutron electron is absorbed and combinging with a proton to turn it into a neutron* so positive plus negtive becomes neutron** protons in nuc are positive, absorbs negative o felectron and turns it into a neutron*

A CAPTURE

so 0e -1 if says capture means that particle is on the left hand side*

Question 12

Rate of radioactive decay

Answer 12

NEVER CHANGES EVER

result of factors internal to the nucleus

as a reslt these things have a fixed halflife, amount of time it takes for half of the material to decay for one thing to turn into another thing stays the same, so if I start as I did with 100 milligrams and I wait 1 half life i will have 50 etc….. the point is that the amount of time it takes to lose half of it will stay the same*

Question 13

E=mc^2

Answer 13

this energy is coming from direct conversion of mass and energy, bits of protons and neutrons are being directly converted into energy! and that energy is what is being given off so we can think abotu how much energy is contained in a certain a mount of mass by using this equation

E=mc^2

Question 14

4 fundamental forces

Answer 14

1. strong nuclear force= attractive force btw protons and neutrons that holds hte nucleus together. inside nucleus strong nuclear force is stronger, but once you leve the nucleus it is very veyr weak only acts at very short distances, so once leave uccleus it doesn’t really do much for you anymore*
2. electromagnetic force talking about atraction and forces of positive and negative charges. this is specifcally about attracking force btw positives and negatives
3. weak nuclear is responsible for beta decay, so never pick that as an answer unless the question is literally what is responsible for beta decay. Also this should not be a correct answer becuase only applies to things going on inside the nucleus* so if sasking you questions about whats going on inside nucelus! then fine, but unless asking you abotu things specifically inside nucleus this isn’t hte answer and distractor- when I say beta decay he means positron and electron so beta decay plus and minus*
4. gravity any two forces with mass attracted, those two forces are really really small so generally ignore them when they are on teh earth but they are there! that is what gravity is!

Question 15

What is a half life?

Answer 15

Question 16

ex. of a half life problem using variables x

Answer 16

Question 17

strong nuclear force and weak nuclear force

Answer 17

Question 18

half life example 2

Answer 18

Question 19

Problem set equations

Answer 19

Question 20

subatomic particles chart

Answer 20

Question 21

How to balance nuclear equations!

Answer 21

Question 22

proton

Answer 22

Question 23

neutron

Answer 23

symbosymbol ¹_on

mass= 1

charge = 0

Question 24

electron

Answer 24

mass = 1/1800

charge= -1

notes= aka beta particle, B-

Question 25

positron

Answer 25

mass= 1/1800 charge= +1 notes= beta + paticle (anitmatter of e-)\*\*

Question 26

alpha particle

Answer 26

mass = 4 charge= +2 helium nucleus 2P and 2n\*\*\*

Question 27

gamma particles

Answer 27

mass= 0 charge = 0 high energy photons

Question 28

Q16. A 10-W light source emits 1,000 Hz photons. Roughly, ho wmany photons does it emit per minute?

Answer 28

Q16 each photon has specific amount of energy, so need to figure out how many they have. so because we can think of energy delivered as energy delivered times energy times n of photons. We can replace that in teh formula SPEFICALLY FOR CASE WHEN POWER SOURCE IS EMITTING PHOTONS\*\* \*IF YOU ARE TALKING ABOUT something not emitting photons that wouldnt work\* if talking about something giving off energy in discrete packets into photons this will for sure be true\* so the answer is 10^33 REMEMBER THIS EQUATION\*\*

Question 29

La

Answer 29

Lanthanum atomic number = 57

Question 30

Q24. What is the resultant atom if a neutron bombards a gold nucleus and in addition to the daughter nucleus, three alpha particles are emitted?

Answer 30

- so "neutron bombards a gold nucleus" so that means we are starting with gold - if a neutron is bombarding the gold nucleus means the neutron is in the reactnts, means STRIKES\* oN1 doesnt matter because we are only adding protons, so protons on the other side wil be 79-6= 73 so the atom will have an atomic number, number of protons of 73 the answer is Tantalum

Question 31

very important equation to use when assked abput how many photons,or protons or electrons.... so if asked "if the mass of a proton is X kg and all of hte mass could be converted into usable energy, how many protons would have to be converted per second to generate 100 W of power?

Answer 31

Question 32

Q. 25 If the mass of a proton is 1.67 x 10 ^-27 kg and all of the mass could be converted into usable energy, how many protons would have to be converted per second to generate 100W of power?

Answer 32

6.6 x 10^11 remember given a mass so we are using E= mc^2 to get the energy! the energy from matter from converting matter directly into energy! keep in kg units becuse that is the standard units\*

Question 33

Q. 26 If the mass of an electron is 9.1 x 10^-31 kg and all of that mass could be converted into usable energy, how many electrons would have to be converted per second to generate 1 mW of power?

Answer 33

also here remember making -3 to -4 in scientific notation KEY= remember making one thing bigger than have to make the exponent smaller\*\*\*

Question 34

Q2 from Chem ch 10 When an atom of 235 U iundergos an alpha dcay followed by a beta decay the resut is an atom of:

Answer 34

Pa so 91 is atomic number becuase it matches the Th90 !!! U92--\> 2He + Th90--\> -1 e + Pa 91\*\* equals 90 and that is what you want\*

Question 35

CHem Q8 the decay of C-14 in an archteological sample is best described by which of the following rate laws:

Answer 35

rate= k [14C] FIRST PORDER\*\*\*\* to lose next 25 % takes just as much as it took to lose first 50% why does that happen, rate going down becuase less of the stuff. so rate laws are always first order for nuclear decays\* electron capture would be electrons and thing capturing it so second order\*Sn2 ex both things in rate law, sn1 only one thing in rate laaw\* nuclear decay have first order rate laws and depend on the amoutn fo stuff present, true for anythin g that has a constant half life\* and the half life remains constant\*

Question 36

Zinc

Answer 36

Zn atomic number 30

Question 37

Au

Answer 37

gold atomic number 79

Question 38

Ag

Answer 38

Element atomic number = 47 group 11 period 5

Question 39

Pb

Answer 39

lead atomic number 82

Question 40

Sn

Answer 40

Tin atomic number 50

Question 41

Hf

Answer 41

Hafnium atomic number 72 electron configuration [Xe] 4f¹⁴5d²6s²

Question 42

Ac

Answer 42

Actinium atomic number 89 Electron configuration: [Rn] 6d17s2

Question 43

Ba

Answer 43

Barium atomic number 56

Question 44

Rb

Answer 44

Rubidium atomic number 37

Question 45

Cs

Answer 45

Caesium atomic number 55

Question 46

Ra

Answer 46

Radium atomic number 88

Question 47

Cu

Answer 47

Copper atomic number 29

Question 48

Co

Answer 48

COBALT NOT COPPER atomic number 27 REMEMBER A in cobalt comes before PPER\*\*

Question 49

Cd

Answer 49

Cadium atomic number 48

Question 50

Rn

Answer 50

Radon atomic number 86 RADON IS THE LAST NOBEL GAS\*\*

Question 51

Kr

Answer 51

krypton atomic number 36 nobel gas

Question 52

Sn

Answer 52

Tin atomic number 50

Question 53

Tl

Answer 53

Thallium atomic number 81 post transition metal

Question 54

Ge

Answer 54

Germanium atomic number 32

Question 55

As

Answer 55

arsenic atomic number 33

Question 56

Se

Answer 56

Selenium atomic number 34