Question

C) Several scientists believe that if they can calculate the half-life of the unknown sample, they may be one step closer to determining where the sample may be from. The line graph below demonstrates the concept of half-life. Using your knowledge of atoms and half-life, explain what exactly this graph shows. What do the x- and y-axes represent? Give an example of a known element and its half-life to help support your answer. (3 points)

Answer 1

I can't read .docx files, but I can help with this. Is there a particular aspect you are stuck with?

Answer 2

I just need help with the part where ity says: Using your knowledge of atoms and half-life, explain what exactly this graph shows. And the part: Give an example of a known element and its half-life to help support your answer.

Answer 3

Ok, do you know what half life means? It is the amount of time it takes for half of the radioactive sample to halve. This can be how long it takes the radioACTIVITY (eg. counts) to halve, or the NUMBER of of radioactive isotopes to halve. All atoms and isotopes have a half life, but some are basically forever, so are stable. But half-life can vary from millionths of a second (very radioactive/unstable) to thousands of years (radioactive but sort of slow).

The graph is that shape because the No. of radioactive nuclei halves every time, so it is a BIG drop from say 200 to 100 in the first half-life time, then a smaller drop from 100 to 50 in the second half life. (You may now see that half-life is not actually half of the total lifetime!).

As for examples, this site lists them for alll the isotopes..!
http://www.iem-inc.com/toolhalf.html

Hope this helps, if you want you can have a go at an answer and post it on here, and i'll take a look, or you can ask anything else you want.

Answer 4

Does this sound right?

This graph shows the number of radioactive nuclei decreasing as time increases. The x-axis represents the time it takes for the radioactive nuclei to diminish, and the y-axis represents the number of radioactive nuclei. An example of an element and it's half-life is cobalt-60 its half-life is 5.27 years.

Answer 5

That looks ok, but the questions asks you to use your knowledge of atoms and half life so you need to put some in.
e.g: (i've added it in to your answer and then left a blank for you..!)
"*When a nuclei is unstable, it can decay into a different atom.* This graph shows the number of radioactive nuclei decreasing as time increases. *N_0 shows the initial number of radioactive nuclei.* The x-axis represents the time it takes for the radioactive nuclei to diminish, and the y-axis represents the number of radioactive nuclei. An example of an element and it's half-life is cobalt-60 its half-life is 5.27 years, *so if there were initially 1,000 cobalt-60 nuclei, after 5.27 years there would be ____ left*."

Answer 6

Thank you!

Answer 7

No problem, i thought that actually you need to also add that the t_1/2 on the graph shows the time it took for half of the radioactive nuclei to decay.

Answer 8

Okay.