Turn on thread page Beta
    • Thread Starter
    Offline

    9
    ReputationRep:
    Hey I am revising for my GCSE Physics mock but got stuck on radioactive decay. Can some please put together an easy step by step explanation that will help me understand this easier? would help a lot
    Offline

    3
    ReputationRep:
    haha me too.. i have my exam in next week and i don't seem to get it.. i want to understand of cramming
    Offline

    17
    ReputationRep:
    alpha, helium nuclei, minus four from the mass number and minus two from the atomic number
    beta, electrons, plus one to the atomic number
    gamma, electromagnetic radiation, doesn't change the mass or atomic number

    the half life is the time taken for half of a sample of radioactive particles to decay

    that's basically what you need to know
    • Political Ambassador
    Offline

    20
    ReputationRep:
    Political Ambassador
    Decay usually happens when an atom has an unbalance of neutrons and protons, so it'll only happen to ISOTOPES of an element

    Isotopes definition - the same element with same number of protons but different number of neutrons - ultimately different mass number.

    To make the element stable the element has to release either alpha, beta or gamma from its nucleus, or all.

    Alpha is 2 protons and 2 neutrons (this is the same as releasing helium nucleus)
    beta is fast moving/high energy electron
    gamma is an electromagnetic wave


    and then there's half life, which is explained above me
    Offline

    17
    ReputationRep:
    (Original post by ihatePE)
    Decay usually happens when an atom has an unbalance of neutrons and protons, so it'll only happen to ISOTOPES of an element

    Isotopes definition - the same element with same number of protons but different number of neutrons - ultimately different mass number.

    To make the element stable the element has to release either alpha, beta or gamma from its nucleus, or all.

    Alpha is 2 protons and 2 neutrons (this is the same as releasing helium nucleus)
    beta is fast moving/high energy electron
    gamma is an electromagnetic wave


    and then there's half life, which is explained above me
    wtf you mean two protons ??????
    it's four
    Offline

    19
    ReputationRep:
    (Original post by defenestrated)
    wtf you mean two protons ??????
    it's four
    nope helium nucleus has 2 protons, 2 neutrons

    He^2+
    Offline

    13
    ReputationRep:
    (Original post by defenestrated)
    wtf you mean two protons ??????
    it's four
    Isn't the number of protons AND neutrons (mass number) four? Then the atomic number (number of protons only) two?
    Offline

    17
    ReputationRep:
    (Original post by z33)
    nope helium nucleus has 2 protons, 2 neutrons

    He^2+
    (Original post by caitlinford3)
    Isn't the number of protons AND neutrons (mass number) four? Then the atomic number (number of protons only) two?
    I GET IT NOW lmao ignore me
    Offline

    19
    ReputationRep:
    (Original post by defenestrated)
    I GET IT NOW lmao ignore me
    X'D dw

    the 4 is the mass - changes the mass number
    the 2 is the charge - changes the atomic number
    Offline

    3
    ReputationRep:
    if that was the only thing to be learnt in this igcse for radioactivity, i would be happy ahah
    Offline

    2
    ReputationRep:
    (Original post by Maz0110)
    Hey I am revising for my GCSE Physics mock but got stuck on radioactive decay. Can some please put together an easy step by step explanation that will help me understand this easier? would help a lot
    Edit: quoted wrong person - oops.

    You might also want to know what gamma,beta,alpha can penetrate.

    For example:

    Gamma cannot go through lead (Pb) high penetration and range

    Beta cannot go through aluminium. Medium penetration and range

    Alpha cannot go through paper. Due to low penetration and low range.

    Alpha particles are also used in smoke dectetors which might be an application question, so I'd suggest reading this page so you can undersrand how it works.

    http://www.bbc.co.uk/schools/gcsebit...opesrev3.shtml
    Offline

    3
    ReputationRep:
    You may also need to know about ionisation.

    Ionisation is basically when nuclear radiation knocks off electrons from an atom, changing its charge. If this happens in an atom of DNA (or inside cells for that matter), it may result in mutations or cancer.

    Ionising power increases as penetrative power decreases, so:
    Alpha: Poorly penetrating, highly ionising
    Beta: Medium penetration, medium ionisation
    Gamma: (Very) HIghly penetrating, poorly ionising

    For example, if a radioactive tracer was to be inserted into a patient, then gamma radiation would be used, as it can pass through materials very easily, with little damage to cells compared to the other types of radiation. An alpha source in the patient would probably kill them.
    • Political Ambassador
    Offline

    20
    ReputationRep:
    Political Ambassador
    (Original post by defenestrated)
    wtf you mean two protons ??????
    it's four
    someone needs to do revision lmao :3
    • Thread Starter
    Offline

    9
    ReputationRep:
    Thankyou to everyone who replied! x
    Offline

    13
    ReputationRep:
    (Original post by Calzs34)
    Edit: quoted wrong person - oops.

    You might also want to know what gamma,beta,alpha can penetrate.

    For example:

    Gamma cannot go through lead (Pb) high penetration and range

    Beta cannot go through aluminium. Medium penetration and range

    Alpha cannot go through paper. Due to low penetration and low range.

    Alpha particles are also used in smoke dectetors which might be an application question, so I'd suggest reading this page so you can undersrand how it works.

    http://www.bbc.co.uk/schools/gcsebit...opesrev3.shtml
    what do you mean by 'low range' etc?
 
 
 

2,105

students online now

800,000+

Exam discussions

Find your exam discussion here

Poll
Should predicted grades be removed from the uni application process
Useful resources

Study tools

Rosette

Essay expert

Learn to write like a pro with our ultimate essay guide.

Thinking about uni already?

Thinking about uni already?

See where you can apply with our uni match tool

Student chat

Ask a question

Chat to other GCSE students and get your study questions answered.

Creating

Make study resources

Create all the resources you need to get the grades.

Planner

Create your own Study Plan

Organise all your homework and exams so you never miss another deadline.

Resources by subject

From flashcards to mind maps; there's everything you need for all of your GCSE subjects.

Papers

Find past papers

100s of GCSE past papers for all your subjects at your fingertips.

Help out other students

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.