Mark the sub-atomic board

Exercise and reference answers

Clues and terms

1. Clue

   Negative particle in cathode rays whose charge to mass ratio Thomson measured

   Item

   Electron

2. Clue

   Lightest positive ion, first got from hydrogen, and its count sets the atomic number

   Item

   Proton

3. Clue

   Neutral particle Chadwick knocked out of beryllium with alpha particles

   Item

   Neutron

4. Clue

   Tiny central region holding the positive charge and nearly all of the mass

   Item

   Nucleus

5. Clue

   Atoms of one element that differ only in how many neutrons they carry

   Item

   Isotopes

6. Clue

   Atoms that share a mass number while their atomic numbers differ

   Item

   Isobars

7. Clue

   Collective name for the protons and neutrons packed into the core

   Item

   Nucleons

8. Clue

   Sum of the proton count and the neutron count of one atom

   Item

   Mass number

9. Clue

   Helium nucleus carrying two positive charges and four units of atomic mass

   Item

   Alpha particle

Instructions

Read each clue and tap the one cell it names, aiming for a line of three.

Explanation