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All 11 Flashcards — Isotopes
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Question
What is an isotope?
Answer
Atoms of the **same element** with the **same number of protons** but **different numbers of neutrons**.
Question
What is the atomic number, Z?
Answer
The number of **protons** in an atom — it defines which element it is.
Question
What is the mass number, A?
Answer
The total number of **protons + neutrons** in an atom.
Question
Isotopes have the same Z but different what?
Answer
The same atomic number Z, but a **different mass number A** (because they have different numbers of neutrons).
Question
Why do isotopes have identical chemical properties?
Answer
They have the **same number of electrons** and the **same electron arrangement**, and chemistry is controlled by the electrons.
Question
Which properties of isotopes differ?
Answer
**Physical** properties that depend on mass — e.g. **density** and rate of **diffusion** — because of the different number of neutrons.
Question
How do you find the number of neutrons?
Answer
Neutrons = **A − Z** (mass number minus atomic number).
Question
Neutrons in chlorine-37? (Z = 17)
Answer
37 − 17 = **20 neutrons**.
Question
What is a radioisotope?
Answer
An isotope with an **unstable nucleus** that decays and gives out radiation; chemically it behaves like the stable isotope.
Question
Give a use of a radioisotope.
Answer
**Carbon-14** for dating, **cobalt-60** for radiotherapy/sterilising, or **iodine-131** for treating the thyroid.
Question
Do extra neutrons change how an atom bonds?
Answer
No — neutrons have **no charge** and do not affect the electrons, so **bonding and reactions are unchanged**.
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Topic 1.2 hub
The nuclear atom
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