General Chemistry: Why Ice Floats on Water
From atoms and bonds to gases, pH and batteries, the chemistry behind everyday things that most people get wrong.
General Chemistry · 50 questions
Try 3 questions
1. When Rutherford fired alpha particles at thin gold foil, almost all passed straight through. What did this show?
- Atoms are mostly empty space
- Alpha particles are tiny electrons
- Gold atoms are extremely soft
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Answer: Atoms are mostly empty space
The rare particles that bounced back revealed a tiny, dense nucleus; the rest of the atom is nearly empty.
2. What determines which element an atom is?
- Its number of electrons
- Its number of neutrons
- Its number of protons
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Answer: Its number of protons
The atomic number counts protons; changing neutrons gives isotopes and changing electrons gives ions of the same element.
3. Carbon-12 and carbon-14 behave almost identically in chemical reactions. How do their atoms differ?
- Carbon-14 has two more protons
- Carbon-14 has two more neutrons
- Carbon-14 has two more electrons
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Answer: Carbon-14 has two more neutrons
Isotopes share the same protons and electrons, so their chemistry matches; only the mass and nuclear stability differ.
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