levo

Radioactivity

The atom and the size of atoms

  • 2 things to know
  • Paper 1

Overview

Protons, neutrons and electrons and where they sit, the tiny dense positive nucleus, atoms as mostly empty space, the sizes of atoms, molecules and nuclei in standard form, and the symbols <<, >> and ~.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Key term

Which two types of particle are found in the nucleus of an atom?

Key term

What is the overall electric charge of the nucleus of an atom, and which particle gives it that charge?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Which two types of particle are found in the nucleus of an atom?

    Model answer

    Protons and neutrons are found in the nucleus.

  2. 2

    What is the overall electric charge of the nucleus of an atom, and which particle gives it that charge?

    Model answer

    The nucleus is positively charged, because of the protons it contains.

  3. 3

    Where are the electrons of an atom found, and what charge do they carry?

    Model answer

    They are found orbiting outside the nucleus and carry a negative charge.

  4. 4

    How does the radius of a nucleus compare with the radius of the whole atom?

    Model answer

    The nuclear radius is far smaller, roughly ten thousand times smaller than the atomic radius.

  5. 5

    Why is almost all the mass of an atom concentrated in its nucleus?

    Model answer

    Protons and neutrons are nearly two thousand times more massive than electrons, and both sit in the nucleus.

  6. 6

    An atom is often described as mostly empty space. Explain why.

    Model answer

    The nucleus and the electrons take up only a tiny fraction of the atom's volume, with nothing in between.

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.