Nuclear model and atomic structure
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Flip to reveal answersWhat are the three subatomic particles and their charges?
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All 12 Flashcards — Nuclear model and atomic structure
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Question
What are the three subatomic particles and their charges?
Answer
**Proton** (+1) and **neutron** (0) in the nucleus; **electron** (−1) around it.
Question
What is a nucleon?
Answer
A particle found **in the nucleus** — i.e. a **proton or a neutron**.
Question
What is a nuclide?
Answer
A specific type of nucleus, fixed by its number of **protons and neutrons** (e.g. carbon-14).
Question
In $^{A}_{Z}\mathrm{X}$, what are A and Z?
Answer
**A** (top) = nucleon number = protons + neutrons. **Z** (bottom) = proton number = number of protons.
Question
How do you find the number of neutrons in a nuclide?
Answer
**N = A − Z** (nucleon number minus proton number).
Question
How many electrons does an ion of charge q have?
Answer
**electrons = Z − q.** A 2+ ion has Z − 2 electrons; a 1− ion has Z + 1.
Question
When an atom becomes an ion, which counts change?
Answer
Only the **electron** count. Protons and neutrons (the nucleus) are unchanged.
Question
What were the THREE observations in alpha-scattering?
Answer
Most passed **straight through**; a few deflected through **large angles**; a very few **bounced straight back**.
Question
How was 'most pass straight through' interpreted?
Answer
The atom is **mostly empty space**.
Question
How was 'a few bounce back' interpreted?
Answer
The positive charge and almost all the mass are in a **tiny, dense, positively charged nucleus**.
Question
What is an alpha particle?
Answer
A small, fast, positive particle = **2 protons + 2 neutrons** (a helium nucleus).
Question
Why don't electrons count toward the relative atomic mass?
Answer
An electron's mass is about **1/2000** of a nucleon's — negligible next to protons and neutrons.
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Structure of the atom
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