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Radioactivity Flashcards

0
Q

Name the types of radiation

A

Alpha beta and gama

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1
Q

Define radioactivity

A

Radioactivity is defined as the spontaneous breaking up unstable nuclei with the emission of one or more types of radiation

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2
Q

Who discovered radioactivity?

A

Henri Beoquerel

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3
Q

Describe how Henri Beoquerel discovered radioactivity

A

He was studying the effect of sunlight on uranium salt crystals. He left some of the salt wrapped in black paper on a photographic plate. He later noticed that the photographic plate had turned foggy. The uranium salt was giving off some kind of radiation. He investigated the radiation being given off and noticed it was being emitted spontaneously. The process was called radioactivity (giving off rays) and the uranium salt was described as radioactive.

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4
Q

Who investigated the radioactivity of uranium salts in more detail?

A

His colleagues Marie and Pierre Curie

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5
Q

How did Marie and Pierre Curie investigate the radioactivity of uranium salts?

A

They purified the salts and discovered two new elements Dolonium and Redium. The Curies and Bacquerel won the Nobel prize for their work on radioactivity in 1903. Marie received a Nobel prize for chemistry for the discovery of the new elements in 1911 (Pierre was dead)

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6
Q

Define an isotope

A

Atoms of the same element which have the same number of protons but a different number of neutrons

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7
Q

Define a radioactive isotope

A

Radioactive form of an element

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8
Q

What are the 3 types of radiation emitted from isotopes?

A

Alpha, Beta and Gama

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9
Q

Describe the charge of alpha particles

A

Particles with a positive charge

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10
Q

Describe the charge of beta particles

A

Particles with a negative charge

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11
Q

Describe the charge of gama rays

A

Rays which are neutral

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12
Q

What do alpha particles consist of?

Also what is this the same as?

A

2 protons and 2 neutrons
A helium atom 4
HE
2

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13
Q

Are alpha particles fast or slow?

A

Slow

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14
Q

How can alpha particles be stopped?

A

Even as easily by the human hand

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15
Q

What can alpha particles harm humans

A

Can cause cancer when inhaled

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16
Q

Alpha particles are emitted by?

A

Radioactive isotopes

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17
Q

Name a radioactive isotope that emitts alpha particles

A

Americium 241

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18
Q

Where can americium 241 be found?

A

In smoke detectors

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19
Q

Alpha particles are helium nuclei, with positive charge and little penetrating ability. Write the chemical equation to represent this.

A

241 237 4
Am -> Np + He + energy
95 93 2

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20
Q

What do beta particles break down into?

A

Protons and electrons

21
Q

Beta particles are emitted what?

22
Q

When in an atom are beta particles emitted?

A

From the nucleus

23
Q

Are beta particles emitted from the nucleus of an atom fast or slow

A

A fast moving stream

24
Are beta particles more or less penetrative then alpha particles?
More penetrative
25
How can alpha particles be stopped?
By 5mm thick aluminium foil
26
Can beta particles penetrate the body?
Yes
27
Can alpha particles cause cancer?
Yes
28
With beta particles the protons remain in the nucleus but explain what happens to the mass and atomic numbers
The mass number remains the same but the atomic number increases by 1
29
When the atomic number of a beta particle increases what is formed?
A new element
30
Carbon 14 is an example of beta decay! What is it used for?
Age determination
31
Give the chemical equation for carbon 14
14 14 0 ( ➡️ N + e + energy 6 7 -1 e= electron atomic number increases by 1
32
What are gama rays emitted by?
Radioactive isotopes
33
Alpha and beta are particles. What is gama?
Rays
34
Do gama rays move fast or slow?
Fast
35
How can gama rays be stopped?
Only by very thick lead
36
What can gama rays do to the human body?
Damage the body and cause cancer
37
Do gama rays have high energy?
Yes
38
Are gama rays have electro negative radiation?
Yes
39
Write the chemical equation for gama rays
60 60 CO ➡️ CO + energy 27 27 Cobalt- 60 used to treat cancer
40
Make a distinction between chemical and nuclear reactions
Nuclear reactions involve changes to the nucleus involving protons and neutrons. They cause elements to change into other elements. Such as alpha and beta decay Chemical reactions involve changes in the distribution of electrons. The element is not changed. Such as gama
41
What happens to an isotope that undergoes beta decay
The atomic number increases by 1 while the mass number remains unchanged
42
Write an equation for the beta decay of radioactive isotopes 19 O 8
19 19 _ O ➡️ F + e 8 9
43
With Alpha decay how much does the mass and atomic numbers decrease?
Mass number decrease by 4 and atomic number decreases by 2
44
Write the alpha decay for this equation 231 Pa 91
231 227 4 Pa Ac + He 91 89 2
45
Define half life
The half life is the time taking for half of the radio isotope to decay
46
Why is the alpha radiation emitted by smoke detectors safe?
It cannot penetrate the human body
47
Why won't you have to replace americium 241 often?
It's half life is 400 years
48
What is carbon 14
A radioactive isotope
49
In living things is the ratio of carbon 12 to 14 constant?
Yes
50
What happens to carbon 14 after death?
After death, carbon 14 decays and the changed ratio plus using its half life is used to find age.

Chemistry (9 decks)

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