1. What is the change in atomic mass number when an atom emits an alpha particle?

QuestionsCategory: Chemistry1. What is the change in atomic mass number when an atom emits an alpha particle?
Lisa Howell asked 7 months ago
1.
What is the change in atomic mass number when an atom emits an alpha particle?

decreases by 2
*decreases by 4
increases by 2
increases by 4

2.
If an isotope decays by the process of beta emission, ____.

the mass number changes

*the atomic number changes

protons are given off

the number of neutrons remains the same

3. 56 25Mn —> _____ + 0/-1e

56/27Co
27/56Mn
56/26Fe
58/24Cr
I don’t know this one.

4.
Which of the following naturally occurring radioisotopes would be most useful in dating objects thought to be millions of years old?

carbon-14; t1/2= 5.73 x 103 years
*potassium-40; t1/2= 1.28 x 109 years
thorium-234; t1/2= 25 days
radon-222; t1/2= 3.8 days

5.
The production of carbon-14 ____.

*takes place in the upper atmosphere

is mostly due to fallout from nuclear explosions

occurs to a large extent in nuclear reactors

is caused by photsynthesis in plants

Thank You.

7 Answers
Lisa Howell answered 7 months ago
I agree with these. The one you have trouble with is below.
3. 56 25Mn —> _____ + 0/-1e

56/27Co
27/56Mn
56/26Fe
58/24Cr
I don’t know this one.

I think it is easier to see if we separate the numbers. I will write that as 25Mn56 ==> -1e0 + X
The numbers to the left must add up on both sides. The numbers on the right do the same.
So 25 = -1 + what? Must be 26
Look on the periodic chart and you find 26 is Fe.
Then 56 = 0 + what? must bre 56. So X is
26Fe56.

Lisa Howell answered 7 months ago
Test

Lisa Howell answered 7 months ago
reee

Lisa Howell answered 7 months ago
you guys suck bro

Lisa Howell answered 7 months ago
reee and Test the person is not asking for your names

Lisa Howell answered 7 months ago
1.B
2.B
3.C
4.B
5.A

Lisa Howell answered 7 months ago
The person above is right

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