levo

Radioactivity

Beta-minus and beta-plus decay

  • 3 things to know
  • Paper 5

Overview

What happens inside a nucleus during β⁻ and β⁺ decay, how the numbers of protons and neutrons, the charge and the mass number change, which nuclei decay each way, and the differences between the two decays.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Key term

Describe what happens inside a nucleus during beta-minus decay, and account for the unchanged mass number and the increased charge.

Key term

Describe what happens inside a nucleus during β⁻ decay.

Key term

State the change in the numbers of protons and neutrons in a nucleus during β⁻ decay.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Describe what happens inside a nucleus during β⁻ decay.

    Model answer

    A neutron changes into a proton, and an electron is created and emitted.

  2. 2

    State the change in the numbers of protons and neutrons in a nucleus during β⁻ decay.

    Model answer

    The nucleus loses one neutron and gains one proton.

  3. 3

    Why does the mass number stay the same in β⁻ decay?

    Model answer

    A neutron is replaced by a proton, so the total number of nucleons is unchanged.

  4. 4

    Why does β⁻ decay leave a nucleus with a greater positive charge than it had before?

    Model answer

    The neutron that changed has become a proton, so the nucleus holds one more positive charge.

  5. 5

    Which nuclei are likely to decay by β⁻ emission?

    Model answer

    Nuclei that have too many neutrons compared with their number of protons.

  6. 6

    Does a nucleus become a different element when it undergoes β⁻ decay?

    Model answer

    Yes, its proton number rises by one, so it becomes the next element up.

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.

1Closed book
2Open book
3Closed book

The 3-step method, run for you

Answer cold, learn it, then prove it stuck. Levo tracks the jump between your first attempt and your last.

Key Concepts of Physics
Motion and Forces
Conservation of Energy
Waves

Cram a whole paper in one sitting

Sort every topic into what you know and what you do not, then drill only the weak ones.

2.5 × = 9000 s.
360027001000

Blank Blitz makes facts automatic

Rapid timed gap-fills on the terms and numbers you need to recall without thinking.

ALength is measured in metres, with the symbol m.
BMass is measured in kilograms, symbol kg.
CTime is measured in seconds, symbol s.

Build It gets the exam shape right

Assemble a full-mark answer from its marking points, in the order an examiner wants them.

Watt means the unit of power, symbol W.
TrueFalse

Test It catches misconceptions

Spot the fault in a statement. The traps are the mistakes students actually make.

721941163128510

Brain Breaks between sessions

Short focus games to reset attention, so the next set lands better than the last.

Every question in Radioactivity, on a schedule.

Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.

Or £46 a year, about £3.83 a month. Cancel anytime.