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.
1.B
2.B
3.C
4.B
5.A
who here is doing connexus ?!?!?!
The person above is right
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.