Science > Chapter 9: Understanding the Atom > Flashcards

Chapter 9: Understanding the Atom Flashcards

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1
Q

what was the early idea that all things were made from

A

all things were made from only 4 elements (wind, water, earth, and fire.)

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2
Q

Who was Democritus

A

Democritus was a early greek philosopher who challenged the idea of all things being made from only 4 elements

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3
Q

what did Democritus belive all matter is made of

A

all matter is made of small, solid, objects, that cannot be divided, created, or destroyed

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4
Q

different types of matter are made from different types of _____

A

atoms

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5
Q

why were democritus’ ideas not widely accepted

A

because he had no way to test them

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6
Q

who was aristotle

A

a philosipher who did not belive or support democtrius

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7
Q

why did many people beilve aristotle

A

because he was very infuencial

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8
Q

who was john dalton

A

a man who used his own research and Democritus’ ideas to develop the atomic theory

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9
Q

what is the first princable of the atomic theory

A

that all matter is made of atoms that cannot be divided, created, or destroyed

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10
Q

what is the second princable of the atomic theory

A

all atoms of the same elemnt are exactly alike and have the mass mass

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11
Q

what is the third princable of the atomic theory

A

atoms cannot be created or destroyed, only rearanged

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12
Q

what is the fourth princable of the atomic theory

A

every compund is made of atoms of different elemnts, combined in a specific way

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13
Q

what is an atom

A

the smallest particle of an element that still has all the properties of that element

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14
Q

what allowed scientists to discover that atoms are made of even smaller particles

A

the Scanning Tunneling Microscope (STM)

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15
Q

who discovered electrons

A

thomson

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16
Q

what did thomson use to discover electrons

A

he worked with cathode rays

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17
Q

what is a cathode ray

A

glass tubes that electricity could travel through

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18
Q

what happens in a cathode ray when air is removed

A

green rays travel from end to end

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19
Q

what happened them thomson placed charged metal plates in the tube

A

the ray would move toward the positive and away from the negative (like a magnet)

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20
Q

since most atoms have no charge, atoms must contain negatively charged particles called ______

A

electrons

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21
Q

what do negatively charged particles (electrons) have a charge of

A

-1

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22
Q

who discovered the nucleus

A

Rutherford

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23
Q

what did Rutherford use to discover the nucleus

A

used alpha particles (dense, positively charged form of radiation) to shoot into atoms

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24
Q

what are alpha particles

A

dense, positively charged form of radiation

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25
what was the expected outcome of Rutherfords experiment
the alpha particles would fly straight through the atoms
26
what was the outcome of rutherfords experiment
most particles traveled straight through or bounced to the side, but some bounced straight back at the source which means the particles must have hit something solid in the center
27
in Rutherfords experiment, what caused the particles that he shot at the atoms to bounce back
a positiveley charged center - the nucleus
28
what are positiveley charged particles in the nucleus called and what is their charge
protons (+1)
29
who discovered the neutral particle of the atom in the neucleus (the neutron)
rutherfords college, James Chadwick
30
look at bhors atomic model in book or notebook
DO IT BAKKKKKAAAA!!!!!!!
31
what is Bhor's atomic model
electrons move in certain orbits around the nucleus
32
true or false? electrons in a certain orbit have a specific energy
true
33
what is the modern atomic model
a nucleus containing protons and neutrons, surrounded by an electron cloud (an area where an electron is likeyly to be located)
34
what are 4 example of subatomic particles
quarks, protons, bosons, and preons
35
what are quarks
sub-atomic particles that make up protons and neutrons
36
what are phontons
a tiny particle of light or electromagnetic radiation
37
what are bosons
"the god particle. Physical proof of all invisible, universe-wide field that gave mass to all matter right after the big bang"
38
what are preons
hypothetical particles that make up quarks and are invisible
39
what are atoms composed of
atoms are composed of protons, netrons, and electrons
40
look at table of parts of an atom in notebook
do it now susser
41
what is the symbol and charge of a proton
symbol= p+ charge= +1
42
what is the symbol and charge of a netron
symbol= n charge= 0
43
what is the symbol and charge of an electron
symbol= e- charge= -1
44
where is the location of a proton in an atom
in the nucleus
45
where is the location of a neutron in an atom
in the neucleus
46
where is an electron found in an atom
in an electron cloud around nucleus
47
what is the relative mass of a proton
1/2 amu
48
what is the relative mass of a neutron
1 amu
49
what is the relative mass of an electron
1/1836 amu
50
what does amu stand for
amu is atomic mass unit
51
what is an element
a substance made from atoms that all have the same number of prtons
52
what is atomic number
the number of protons in an atom of an element
53
does every element have a different number of protons
yes, every element have a different number of protons
54
what will the electrons and protons be like in a neutral atom
a neutral atom will have the same number of electrons as it has protons (balances so the overall charge is neutral)
55
what are neutrons
particles in the nucleus with no charge
56
what is it called when atoms of the same element have a different number of protons
Isotopes
57
how many isotopes do elemnts have
most elements have several isotopes
58
what is mass number
numnber of protons+number of neutrons
59
study mass number periodic table
go lil susser
60
what is average atomic mass
the weighted average mass of an elements isotopes
61
what is average atomic mass based off of
based on how much of elements isotopes of an elements is present in nature
62
what is radioativity
the ability of an element to spontaneously change into another form or element
63
what is Henri becquerel discover
discovered that mineral containing uranium gave off energy
64
how did henri becqueral make his discovery
a photographic plate left in a drawer has the image of the mineral that was sitting on top of it
65
what does radioactive mean
elements that spontaneously emit radiation
66
what is radiation from uranium made of
made of particles and energy
67
what are 3 types of decay that all occur naturally
nuclear decay, alpha decay, and beta decay
68
what is nuclear decay
the process of an unstable form into another more stable nuclei by emitting radiation
69
what does alpha decay release
releases alpha particles (2 p+ & 2 n- and a nucleus)
70
what is an example of alpha decay
thorium 232 become radium 228
71
how deadly is aplha decay
can cause skin burns but not extremely deadly
72
what are particles like in alpha decay
particles move very fast, but are easliy stopped by colissions with atoms
73
radiation can be blocked by what
a piece of paper
74
what happens in beta decay
a neutrons inside a unstable atom changes into a proton and a negatively charged beta particle
75
what happens to atomic mass and atomic number in beta decay
atomic mass stays the same, but the atomic number increases
76
whats an example of beta decay
carbon 14 becomes nitrogen 14
77
do alpha or beta particles move faster
beta particles move faster than alpha particles
78
what can beta decay be blocked by
can be blocked by 5 mm sheet of aluminum
79
how harmful is beta decay to humans
can travel into the human body and damage cells
80
what happens in gamma radiation
high levels of energy rays are released (similar to x-rays)
81
what is the charge of gamma radiation
gamma radiatio has no charge
82
what does it take to block gamme radiation
1 meter of cement to block
83
what harmful is gamma radiation to humans
can pass through body causing severe damage
84
what can radiation therapy be used to do
can be used to destroy cancer cells in patients
85
what is an Ion
an atom that is not neutral due to losing or gaining electrons
86
when does a positive ion occur
occurs when a neutral atom loses 1 or more electrons
87
what happens when a neutral atom when losing 1 or more electrons
results in having more positive protons than negative elctrons
88
how do people show an atom is positive
you write it with a + superscript
89
what does Na+ mean
means that this is a positive sodium with one or more proton that electron
90
when do negaive ions occur
occurs when an atoms gains 1 or more electrons
91
what does an atom gaining 1 or more electron result in
results in an overall negative charge because it has more electrons present than protons
92
what is an overall negative charge with more electrons present that protons shown in a superscript
shown with a -
93
whats an example of a - being used in a superscript
0-2 mens that it is a negative oxogen ion with 2 or more electrons that protons
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