Chemistry · KS3 Y8 · The Periodic Table
The periodic table
The periodic tableFree4:07Heddy Score 3 of 7, below the standard
What you need to know
- For a neutral atom, the atomic number gives the number of protons and electrons; an ion has gained or lost electrons, so its charge must be used to find its electron count.
- The mass number of a particular isotope is the total number of protons and neutrons; subtract the proton number from that isotope’s mass number to find neutrons.
- Relative atomic mass is a weighted average of isotope masses, so rounding it only estimates a common mass number and does not identify the mass number of every element.
In this clip
Runs 4:07, from 0:00 to 4:07 of the full video.
Heddy ScoreSeven checks every clip must pass before students see it: trusted, on the map, accurate, focused, accessible, safe, and proven by students.3/7, Below the standard
See the seven stars
- Trusted source · passed. The creator's own upload, live and playable here.
- On the map · not judged yet. A teacher watched it: it mainly teaches this map topic.
- Spec-true · not judged yet. Accurate, and right for the current UK specification.
- Focused · passed. One idea, short enough to watch in one go.
- Accessible · passed. Good captions, clear sound and pictures.
- Safe for children · not judged yet. Right for 11 to 16 year olds, with no sales pitch.
- Proven · not judged yet. Earned from our students: they learn from it, find it helpful and watch it to the end.
Our students
Not enough students yet
Our own students' answers. These are what move ★7 Proven.On YouTube
How the Heddy Score works999K views · 9.44K likes · MooMooMath and Science 642K subscribers
As reported by YouTube on 2026-11-02. Not part of the Heddy Score.Why we picked it
The worked periodic-table examples practise finding proton and electron numbers and calculating neutrons when an isotope mass number is known.
MooMooMath and Science on YouTubechecked 2026-10-20
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