Answer:
16) 6 electrons
17) 6 protons
18) 6 neutrons
19) 4 electrons
20) 6
Step-by-step explanation:
There are 6 electrons on the rings in total and 6 protons inside the nucleus. If you count the black cir les, there are 6 of them so there are 6 neutrons. Knowing that the inner ring can only hold 2 electrons the most, 6-2= 4. So there are 4 electrons on the outer ring. Knowing that you can get the atomic number based on the number of protons an atom have, the at pool mic number would be 6.