2. Which of these has a negative charge?
Protons Neutrons Electrons Quarks None of these
3. Which of these has a negligible mass?
Protons Neutrons Electrons Atoms None of these
4. How many protons in sodium-23?
11 12 23 1 0
5. Which of these is a pure substance?
Blood Ocean Brass Wine Table Salt (NaCl)
| about us | contact us
tutorials index | organic
chemistry | practice tests | online
quizzes | reference tools
site copyright (c) 2002 to neopages.com