1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

B Confusion with the terms: Reactive, Unstable and Radioactive

  1. Mar 14, 2016 #1
    Really wishing I had paid more attention in high school. I assumed that reactive meant that the element either needed to gain or lose electrons causing it to "want" to grab onto another or be grabbed. Sodium being an example. If I am correct with that part, this next part is where I am picking up some confusion. Once it is straightened out I will probably have a good number of other questions to ask. What are the differences with reactive, and unstable? And where does radioactive come into play among them, if at all? I will wait for an answer before I throw more into this thread. I am sorry if this happens to be a very simple question and annoys anyone. I have grown to not fully trust many sources and prefer talking with a human about the questions over using a restrictive search engine.
  2. jcsd
  3. Mar 14, 2016 #2


    User Avatar
    Science Advisor

    I'm sure others here can give a much more detailed explanation, but here goes:

    Reactive - I agree.

    Unstable - Usually refers to something (an assembly) that comes apart or changes form, often spontaneously or with minimal external input

    Radioactive - When a sub-atomic particle (Alpha ray, Gamma ray, ...) is ejected from an atomic nucleus
  4. Mar 14, 2016 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    If an element is chemically reactive, that means it is easy for it to combine with other elements to form a compound. Sometimes, this reaction occurs spontaneously; other times, another agent, like a spark, will initiate the reaction.

    If a compound is unstable, that means it readily decomposes into one or more of its constituent elements or other compounds. A compound like nitroglycerin is unstable in the presence of heat or shock, but it can be treated to render it safe to handle.

    The above are types of chemical reactions or processes, where entire atoms combine to form compounds or compounds split up into their constituent parts.

    On the nuclear level, certain changes can occur spontaneously to certain atoms which turn one element into another. An element is unstable if it emits radiation as it undergoes these atomic changes. Radiation occurs in three forms: alpha, beta, and gamma. An element which emits one or more of these types of radiation is said to be radioactive:

  5. Mar 14, 2016 #4
    I think the difference of unstable compounds and unstable elements may have caused my confusion. So He-4 is stable and nonreactive, Na-23 would be stable and reactive, any isotope of Fr is reactive and unstable, and He-7 is nonreactive and unstable? Am i beginning to grasp this?
  6. Mar 14, 2016 #5


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Yes, you are.

    An element's location in the Periodic Table can tell you how reactive it might be and what other elements it is likely to react with.

    There isn't a simple chart of element isotopes which can tell you which isotopes are stable and which will decay quickly, so you pretty much have to research this information for each element.
  7. Mar 15, 2016 #6
    Thats what I have been doing, the researching of the isotopes that is. This sort of thing was never an interest to me so I never paid full attention when it was being taught and now I find myself working on a personal project and needing to know such things. I have about 8 more questions from the list of questions I started with but I am going to see if I can answer them on my own first. Thank you all for your time!
  8. Mar 15, 2016 #7
    Google "chart of the nuclides"
  9. Mar 17, 2016 #8
    That's pretty neat, maybe a bit above me but I definitely find it to be interesting. I think i understand it enough to help me with my questions and if I don't, I will. Thanks.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted