Chemistry Unit 1
Atom lab
Like the PhET sim from class — but every number you need for the Major updates as you build. Try: add a proton to fluorine. Then put it back and add a neutron instead. What changed each time?
Build an atom
proton (+1) neutron (0) electron (−1) valence electron
199FFluorine-19Z = 9 · A = 9 + 10 = 19Neutral: electrons = protons ✓
Arrangement2, 7
Core e⁻2
Valence e⁻7
Protons+1 · nucleus9
Neutrons0 · nucleus10
Electrons−1 · energy levels9
Load an element (most common isotope)
Alkali metal Alkaline earth metal Metal Metalloid Non-metal Halogen Noble gas
Isotopes side by side
126CCarbon-126 p · 6 n · 6 e
146CCarbon-146 p · 8 n · 6 e
Same protons (6) → same element. Different neutrons (6 vs 8) → different mass numbers → isotopes.