For Argon (Ar), here are the details you provided along with additional information:
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Atomic Number: 18
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Atomic Mass: 39.948
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Number of Protons: 18 (the atomic number indicates the number of protons)
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Number of Electrons: 18 (in a neutral atom, the number of electrons equals the number of protons)
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Number of Neutrons: To find the number of neutrons, you can use the formula:
\[ \text{Number of Neutrons} = \text{Atomic Mass} - \text{Number of Protons} \]
Since the atomic mass is approximately 39.948 and the number of protons is 18:
\[ \text{Number of Neutrons} \approx 39.948 - 18 \approx 21.948 \]
Neutrons are typically whole numbers, so rounding gives about 22 neutrons.
Summary:
- Atomic Number: 18
- Atomic Mass: 39.948 (approximate)
- Number of Protons: 18
- Number of Neutrons: 22 (approximate)
- Number of Electrons: 18