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Checking an Excited Atom Against the Table 4 questions
Checking an Excited Atom Against the Table
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A classroom display records how many electrons occupy each shell of three particles. A particle can be excited when an electron moves to a higher shell. In this model the row of an element in the periodic table corresponds to the occupied shells of its neutral ground-state atom.
| Record | Protons | Electrons in shells 1, 2, 3, and 4 |
|---|---|---|
| P | 12 | 2, 8, 2, 0 |
| Q | 12 | 2, 8, 1, 1 |
| R | 12 | 2, 8, 1, 0 |
Question 1
Which pair has the same nuclear charge and the same total number of electrons but a different shell arrangement?
- P and Q
- P and R
- Q and R
- All three
Question 2
Explain why Q fits excitation from P while R fits loss of an electron from P.
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The display confirms P is the neutral ground-state record. The periodic table lists magnesium in period 3.
Question 3
A student puts Q in period 4 because its fourth shell is occupied. Use the records and the model rule to evaluate the claim.
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Question 4
A neutral sodium atom also has the arrangement 2, 8, 1. Explain how a proton count can distinguish it from R.
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