Protons, neutrons and electrons

Answer Key - Grade 8 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Ari reads that an iron atom has mass number 56 and 30 neutrons. How many protons does it have?

   26 protons
2. 2.

   Bo reads that a copper atom has mass number 63 and 34 neutrons. How many protons does it have?

   29 protons
3. 3.

   Esme reads that a boron atom has mass number 11 and 6 neutrons. How many protons does it have?

   5 protons
4. 4.

   Jun says electrons sit inside the nucleus, next to the protons. Agree or disagree?

   • Agree: opposite charges sit together
   • Disagree: electrons are around the nucleus
   • Disagree: electrons are outside the whole atom
   • Agree: the nucleus holds the whole atom
5. 5.

   Kira says a neutron has a small positive charge. Agree or disagree?

   • Disagree: it is negative
   • Agree: it is a weak proton
   • Agree: it sits with the protons
   • Disagree: it has no charge

6. Read this first

   Table (IUPAC data)

   Atomic number, symbol, name. 5 B boron; 6 C carbon; 7 N nitrogen; 8 O oxygen.

7. 6.

   A carbon atom has 6 protons and 6 neutrons. If it had one more neutron, what would it be, Milo?

   • Oxygen
   • Nitrogen, the next element
   • Boron, since it is heavier
   • Still carbon, with mass number 13
8. 7.

   Imagine the same carbon atom with one more proton instead. Using the table, what would it be, Noah?

   • Element 13, from the mass number
   • Still carbon, since neutrons decide
   • Nitrogen
   • Boron
9. 8.

   Atomic number, symbol, name. 16 S sulfur; 17 Cl chlorine; 19 K potassium. Atom X has 17 protons and 18 neutrons. Atom Y has 17 protons and 20 neutrons. What are they, Pia?

   • Both chlorine
   • Both sulfur
   • X is chlorine and Y is potassium
   • Two different elements, since neutrons differ
10. 9.

    Ren checks three classmates' atom models. Which one is right?

    • Neutrons marked −, electrons marked +
    • Electrons drawn inside the nucleus
    • Protons and neutrons in the center, electrons around
    • Particles spread evenly through the atom
11. 10.

    Tala labels an atom model's key. Which set of labels is right?

    • Proton +, neutron −, electron −
    • Proton −, neutron no charge, electron +
    • Proton +, neutron +, electron −
    • Proton +, neutron no charge, electron −