About this tool

A random element comes up with its symbol, name and atomic number. The student draws its atom: tap a ring to put an electron on it, tap an electron to take it off, and add shells as they need them. There are also plus and minus buttons for each shell.

When they press Check, a correct diagram shows the arrangement, such as "Correct! Chlorine is 2, 8, 7." A wrong one gets a hint about the first mistake, without giving the answer away:

• The wrong number of electrons, with a reminder that it matches the atomic number.
• Too many in a shell. The first shell holds 2 and the next two hold 8.
• Starting a new shell before the one inside it is full.
• An empty shell left in the drawing.

After two wrong tries, Show me the answer appears. The page counts how many elements were right first time. Every element comes up once before any repeats.

Settings

• Elements. 1 to 10, 11 to 20, or all 20.
• Nucleus. Students also type the protons and neutrons, using the mass number shown on the card.

Good for

• Practice after a lesson on atomic structure
• Revision before a test
• Students working at their own pace