EasyChemistryHigh School (9–10)GeneralStructure of the Atom › Subatomic Particles and Atomic ModelsConceptualBoard Exam
Name the particle in each case. It is negative and has almost no mass…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Name the particle in each case.
- It is negative and has almost no mass.
- It is in the nucleus and has no charge.
- It is in the nucleus and has a charge of .
- Its number decides which element the atom is.
Which of the three particles was found last, and why was it the hardest to find?
Need a reminder? The key ideaShow
An atom has three kinds of particle. The proton has a charge of and a mass of about . The neutron has no charge and a mass of about . The electron has a charge of and a mass of only . The charge of one proton is .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) The electron.
Step 2. (b) The neutron.
Step 3. (c) The proton.
Step 4. (d) The proton: the number of protons is the atomic number.
Step 5. Found last. The neutron, found by Chadwick in 1932. It has no charge, so electric charges do not move it, and it is hard to detect.
Answer: electron, neutron, proton, proton; the neutron was found last.
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