Quiz about Radioactive decay

Question 1

How many protons are in this atom?

Accepted Answer

3

Answer

4

Answer

6

Answer

10

Question 2

How many neutrons are in this isotope of Uranium?

Accepted Answer

143

Answer

235

Answer

92

Answer

327

Question 3

The half-life of Zn-71 is 2.4 minutes. Starting with 100.0 g, how many grams would remain after 4.8 minutes (2 half-lives)?

Accepted Answer

25.0 g

Answer

100.0 g

Answer

50.0 g

Answer

8.5 g

Question 4

What is likely to happen to unstable nuclei with too many, or too few, neutrons?

Accepted Answer

They will decay by emitting radiation.

Answer

They will loose all their electrons.

Answer

They will bond with other atoms.

Question 5

After how many half-lives would you only have 12.5% of the original isotope left?

Accepted Answer

3

Answer

1

Answer

2

Answer

4

Question 6

What percentage of the original isotope is left after 1 half-lives?

Accepted Answer

50%

Answer

100%

Answer

75%

Answer

25%

Question 7

What percentage of the original isotope is left after 2 half-lives?

Accepted Answer

25%

Answer

100%

Answer

75%

Answer

50%

Question 8

The half-life of a substance is 6000 years. How long would it take for half the substance to change from a radioactive isotope to a stable substance?

Accepted Answer

6000

Answer

3000

Answer

9000

Answer

12000

Question 9

Carbon dating is used to determine the age of a fossil. Less than 7% of the original amount of radioactive carbon-14 is left. How many half-lives would have passed?

Accepted Answer

4

Answer

1

Answer

2

Answer

3

Question 10

Carbon dating is used to determine the age of a fossil. About 80% of the original amount of radioactive carbon-14 is left. How many half-lives would have passed?

Accepted Answer

less than 1

Answer

more than 2

Answer

about 3

Answer

exactly 4

Question 11

How much of the original isotope is left after 3 half-lives?

Accepted Answer

one eighth

Answer

Half

Answer

One quarter

Answer

one sixteenth

Question 12

How much of the original isotope is left after 2 half-lives?

Accepted Answer

One quarter

Answer

Half

Answer

one eighth

Answer

one sixteenth

Question 13

What makes something radioactive?

Accepted Answer

an unstable isotope in the nucleus

Answer

elements with an atomic number above 81

Answer

contaminated sewage in the lagoons

Answer

It decays over time breaking into foul chemicals

Question 14

When an unstable radioactive atom decays, it usually turns into:

Accepted Answer

a more stable atom

Answer

a less stable atom

Answer

the exact same atom but with less pure energy

Answer

empty space

Question 15

Radiometric dating is possible because the rates of decay of radioactive isotopes _____.

Accepted Answer

are mathematically constant

Answer

change over time

Answer

change from place to place

Answer

vary widely

Question 16

The time it takes for 50% of the nuclei in a radioactive sample to decay to its stable isotope is called _____.

Accepted Answer

the half-life

Answer

the daughter product

Answer

geologic time

Answer

the half-time

Question 17

If the half-life of a radioactive group of atoms is 100 years, then how old is the substance if there have been two half-lives?

Accepted Answer

200 years

Answer

25 years

Answer

400 years

Answer

800 years

Question 18

The table shows the radioactive decay of carbon-14. Part of the table has been left blank.

After 17,100 years, approximately what percentage of the original carbon-14 remains?

Accepted Answer

12.5%

Answer

15%

Answer

6.25%

Answer

3.125%

Question 19

Isotopes are the same element that have different number of _______.

Accepted Answer

neutrons

Answer

neutral

Answer

protons

Answer

electrons

Question 20

In the symbol ²⁰⁶₈₂Pb what does 206 stand for?

Accepted Answer

Mass number

Answer

Atomic number

Answer

Atomic mass

Answer

Number of protons

Question 21

How long will it take for a 28-gram sample of radon-222 to decay to 3.5 grams? the half-life of radon-222 of 3.82 days

Accepted Answer

11.46 days

Answer

15.28 days

Answer

3 days

Answer

4 days

Question 22

The half-life of strontium-90 is 25 years. How much will remain after 100 years if the initial amount is 4.0 g?

Accepted Answer

6.25 g

Answer

3.0 g

Answer

0.25 mg

Answer

0.3 g

Question 23

The half-life of Zn-71 is 2.4 minutes. Starting with 100.0 g, how many grams would remain after 7.2 minutes?

Accepted Answer

12.5 g

Answer

100.0 g

Answer

50.0 g

Answer

8.5 g

Radioactive decay

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