Labs / Chemistry
Electron Shells
Every element is just a nucleus with electrons stacked into shells. Drag across the atom or slide the atomic number from hydrogen up to calcium, and watch each shell fill by the 2, 8, 8 rule. The glowing outer electrons are the valence electrons — the ones that do all the bonding.
Element Sodium (Na)Config 2, 8, 1Valence 1
What to try
- Which elements end up with a completely full outer shell, and why might those be the ones that almost never react?
- Sodium has 1 valence electron and chlorine has 7 — what does that hint about why they snap together into salt?
- As you climb from Z = 1 to Z = 20, does the valence count keep rising, or does it reset? What pattern do you notice?
- Why does the third shell stop at 8 here and hand the next electron to a brand-new fourth shell?
- Two elements can share the same valence count — can you find a pair, and would you expect them to behave alike?