2. Which of these has a negative charge?
Protons Neutrons Electrons Quarks None of these
3. Which of these can an element have a different number of?
Protons Neutrons Electrons All of these None of these
4. How many protons in sodium-23?
11 12 23 1 0
5. Which of these has 23 protons?
Scandium Titanium Vanadium Chromium None of these
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