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Flashcards in Test 3- Atomic Theory Deck (75):
1

Antoine Lavoisier main

Law of conservation of matter

2

Joseph Louis Proust main

-Law of Composition
-Law of Multiple Proportions
-Combustion reactions

3

John Dalton

-Atomic Theory of Matter
-solid sphere model

4

Sir William Crookes

- Cathode Ray Tube

5

J.J. Thompson

Plum pudding model

6

Robert Milikan

Oil drop
Determined mass and charge of an electron

7

Henri Bacquerel

Photographer

8

Ernest Rutherford

-Two experiments:
-Isolated and identified alpha, beta and gamma radioactive emissions
-gold foil experiments, and
-Planetary model

9

Aristotle

Thought everything was made up of 4 elements- earth, air, water, and fire. Also, student of Plato

10

Democritus

Student of Aristotle but thought that he was wrong. Thought that everything was made up of Atoms- “indivisible” in Greek. 400 BCE

11

Between these philosophers and the modern exploration of matter

was something called Alchemy- the making of gold

12

Antoine Lavoisier

-Late 1700’s
-Father of Chemistry
-Worked in lab and took quantitative data
-Figured out that the mass of reactants=mass of products
-Law of Conservation of mass (matter)- matter can not be created or destroyed in any chemical reaction.
-E=mc^2 (Einstein) where E=energy, m=mass, and c^2=speed of light. I have no idea how this related to anything but it was in out notes ☺

13

Joseph Louis Proust

-1799
-Law of Constant proportion/Law of definite composition- The ratio of the elements in a compound remains the same. Ex. Water always has 2 hydrogen and 1 oxygen.
-Law of Multiple Proportions- Same element can be in different compounds as long as ratio changes. Ex. H2O= 2:1 while H2O2= 1:1

14

Law of Constant proportion/Law of definite composition-

The ratio of the elements in a compound remains the same. Ex. Water always has 2 hydrogen and 1 oxygen.

15

Law of Multiple Proportions-

Same element can be in different compounds as long as ratio changes. Ex. H2O= 2:1 while H2O2= 1:1

16

Combustion reactions

-C X Hy+O2⇒CO2+H2O
-C4H10+a lot and C8H18+a lot⇒complete combustion
-C X Hy+O2 (limited)⇒CO+H2O (incomplete combustion)
-C X Hy+O2 (less O2 than above)⇒C+H2O (incomplete combustion)
-⇒Yield sign, points to direction of reaction

17

John Dalton

-1803
-Atomic Theory of Matter:
1. Each element is composed of extremely small particles called atoms (Democritus)
2. All atoms of the same element are identical in chemical and physical properties, but differ from those of any other element.
3. Atoms are neither created nor destroyed. Chemical reactions consist of the combination, separation, or rearrangement of atoms (Lavoisier)
4. A given compound always has the same relative number and kinds of atoms (Proust)
-Soil Sphere model

18

The Atomic Theory of Matter-John Dalton

1. Each element is composed of extremely small particles called atoms (Democritus)
2. All atoms of the same element are identical in chemical and physical properties, but differ from those of any other element.
3. Atoms are neither created nor destroyed. Chemical reactions consist of the combination, separation, or rearrangement of atoms (Lavoisier)
4. A given compound always has the same relative number and kinds of atoms (Proust)

19

Sir William Crookes

-1870s
-Cathode Ray Tube
-Crookes noted that the green glow moved with a magnet and moved a paddle wheel

20

J.J. Thompson

-Identified negative component in matter and deduced that there must be a positive part because matter is neutral
-Dalton was wrong about model of atom. Thompson proved the presence of electrons
-Plum pudding model/sea of electrons model- number of number of P+= number of e-

21

Robert Millikan

-Oil Drop experiment
-Determined the mass and change of an electron

22

Henri Becquerel

-Photographer
-Photographed uranium- a radioactive rock and noticed exposure

23

Ernest Rutherford- Radioactive emissions

-Isolated and identified alpha, beta and gamma radioactive emissions
-3 types of radioactive emissions
-Ex. Of Alpha decay: 238(92)U⇒4(2)α+234(90)Th
-Example of Beta Decay: 214(82)Pb⇒214(83)Bi+0(-1)β
-Beta decay- neutron changes into a proton (stays in nucleus) and electron (β particle) that flies away.
-Rutherford determined alpha and Beta particles
-Gama in energy not a particle

24

Ernest Rutherford-Gold Foil

-Gold foil experiment: A ray of gama particles was shot through a piece of gold foil with photo film around it. Most of the exposure was directly across showing that most of the particles went straight though. However, some of the particles deflected showing that it bounced off something (nucleus)
-The particles were positive so since the particles deflected, this means that the nucleus is positive since the same charge repels each other.
-Since most of the rays went straight through, this showed that it was mostly empty space.
-Three conclusions:
1. Atoms have a nucleus
2. The nucleus is positive
3. Mostly empty space

25

Ernest Rutherford- Atomic model

-Model number 3 proposed by Rutherford
-Planetary model
-Move in circles so they don’t stick to Nucleus
-Like an amusement park ride

26

Evolution of models of the atom

-Three models: Solid sphere, plum pudding, and planetary.
-The first was solid sphere. Proposed by John Dalton before experiments like the cathode ray tube were done to find out what was inside an atom.
-The second was the plum pudding/sea of electrons model. J.J. Thompson proposed this. He set up another cathode ray but with metal plates on the top and bottom. When the rays moved toward the positive part, he deduced that there must be a positive part since matter is neutral. He therefore identified negative component in matter, proving Dalton wrong. Protons=electrons.
-The third model is called the planetary model proposed by Ernest Rutherford. He said that electrons move in circles around the positively charged nucleus so that they don’t stick together.

27

Subatomic Particle- Relative charge

Proton- +1
Neutron- 0
Electron- -1

28

Subatomic Particle- Mass number

Proton- 1
Neutron- 1
Electron- 0

29

Subatomic Particle- Nuclear symbol

Proton- 1(1)P; 1(1)H; P+
Neutron- 1(0)n or n°
Electron- 0(-1)e or e-

30

Subatomic Particle- location

Proton- Nucleus
Neutron- Nucleus
Electron- Around the nucleus but still inside the atom

31

Relative mass

atomic mass unit (amu) is 1/12 the mass of a carbon-12 atom

32

Nuclear symbol

mass P+n(# of P)X

33

Nucleus-

P+ and n°- also called nucleons

34

Number of protons is called

the atomic number

35

Element is defined by

Number of protons

36

Mass number=

P+ + n°

37

Electrons are equal to

the number of Protons

38

bottom nuclear symbol

-Atomic number
-Number of protons
-Number of electrons (unless ion)

39

Top of nuclear symbol

Mass number

40

How to find the number of neutrons

mass # - # of protons

41

In 14(6)C there are

-6 protons
-6 electrons
-8n(14-6)

42

If given something like C-12

-12 is the mass number.
-You know there are 6 Protons because its carbon, therefore there are 6 electrons.
-There is 6 neutrons since 12-6=6

43

Isotope

An atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass) Ex. C-14 and C-12

44

Ion

-An atom that has lost or gained electrons
-Gained electron-Anion-Negatively charged
-Lost election-Cation-Positively charged

45

86(37)Rb+2

The +2 tells us that its an ion. Since its positive, it has a positive charge which means that is loses electrons. P+=37, n°=49, and e-=35 (37-2)

46

Nucleons

protons and neutrons

47

Electrostatic attraction

Protons and electrons attract

48

Electrostatic repulsion

e-+e- and P+P repel

49

(Strong) Nuclear force

the interaction that binds P+n, P+P, and n+n in nucleus.

50

A nucleus is stable when

nuclear force and electrostatic repulsion balance out. This occurs when the ratio of n to P is between 1:1 and 1.5:1. This is also called the band of stability

51

No more than ___ protons before nucleus is unstable (radioactive)

-83
-so Bismuth is ok but starting with Polomium, its not.

52

Nuclear Reaction

A change in the nucleus of an atom

53

Chemical Reaction

Atoms are just rearranged/combined, not changed

54

Transmutational Reaction

Change in identity of a nucleus as a result of the number of protons changing.

55

Alpha particle emissons

-Rutherford-radioactive particles- Alpha particles:
-4(2)α- 2P and 2n from nucleus
-Ex. 238(92)U⇒4(2)α (leaves nucleus)+ 234(90) Th. This is an example of Radioactive decay and Tansmutation

56

Radioactive decay happens

spontaneously and by itself

57

Beta particle emissions

-Beta particles- n° changes into P+ and e-, P+ stays, e- is emitted
-Ex. 214(82)Pb⇒214(83)Bi + 0(-1)β. Notice how the bottom number changes as one neutron is changed into a proton, changing the element since the number of protons determines the element.

58

Nuclide

atom, but in nuclear activity

59

radioactive decay

spontaneous disintegration of a nucleus into a slightly lighter nucleus accompanied by emission of particles, electromagnetic radiation, or both. Both α and β are examples of radioactive decay

60

Gamma emissions

Gamma is the electromagnetic radiation that’s given off.

61

Health risks-

Alpha-low, Beta-medium, Gama-high

62

Half life

The time required to half of the atoms of a radioactive sample to decay.

63

Formulas for half-life:

1. Number of half-lives=time elapsed X 1 half-life/14.3 days
2. Amount remaining= original amount X ½ for each half-life

64

Fusion

Low-mass nuclei combine to form a heavier, more stable nucleus. Ex. Nuclear reactions

65

Fission

A very heavy nucleus splits into more stable nuclei of intermediate mass. Ex. Sun, atomic bombs

66

Fission and Fusion are both

not spontaneously forced

67

E=mc^2

-nuclear reaction energy formula
-Einstein

68

Experiments with cathode rays (crooks tube) being deflected by a magnetic fields show that cathode rays are composed of particles that are.

-Magnetic (because its Crooks and he didn’t know about negative charge yet)

69

Cathode rays are composed of particles that are now known as

-Electrons

70

In 1911, Ernest Rutherford conducted his now famous gold foil experiment. During the experiment, alpha particles bombarded a thin piece of gold foil. The alpha particles bombarded a this piece of gold foil. The alpha particles were expected to pass easily through the gold foil. Every now and then, however, an alpha particle bounced back- an unexpected result. Rutherford concluded that these particles were striking:

-A tiny region of particle charge

71

Rutherford called the region that deflected alpha particles:

A nucleus

72

The total volume of the nucleus of an atom is:

-Very small compared with the rest of the atom

73

Why did the mass increase in the open container?

-As matter burns, the oxygen in the air combines with the matter, adding to its overall mass. In the closed container, there was very little and limited oxygen to combine with the matter, so the mass did not increase, but remained the same due to the law of the conservation of matter.

74

Ion

an atom, radical, or molecule that has gained or lost one or more electrons and has a negative or positive charge

75

atom

the smallest unit of an element that maintains the chemical properties of that element