Track quiz
Here is the whole track on one screen.
| Idea | What to remember |
|---|---|
| The piece has parts | Cathode rays are electrons. Every atom has them. |
| Something with a charge | Electron −1, proton +1. An atom is neutral. |
| Where the mass sits | A tiny, dense nucleus. Most of an atom is empty space. |
| A picture that had to change | Dalton, then Thomson, then Rutherford, then Bohr. |
| Shells | K, L, M hold 2, 8, 18. The outermost shell holds at most 8. |
| Which atom is it | Z = protons. A = protons + neutrons. |
| Filling the shells | K takes 2. L takes 8. M takes only 8 in the first 18 elements. The outermost shell holds at most 8. |
| The outer shell decides | Generally, fewer than 4 outer electrons: lose. More than 4: gain. Exactly 4: share. |
Cathode rays were the same for every cathode metal and every gas. What did this show?
Atoms are neutral. In Thomson's model, what balances the negative electrons?
In the gold foil experiment, what did a few bounced-back particles show?
Which is the correct order of the four atom models?
Why did Rutherford's model fail to explain a stable atom?
How many electrons can the M shell hold?
An atom has 14 protons and 14 neutrons. What is its mass number?
What is the electronic configuration of phosphorus (Z = 15)?
Chlorine is 2, 8, 7. What does it tend to do?
Where does most of an atom's mass sit?
Read Chapter 8 of your book this week. It is Journey Inside the Atom.
Next comes Atomic Foundations of Matter.