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8th grade Protons, neutrons and electrons worksheet

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Protons, neutrons and electrons

Grade 8 Science Worksheet - Challenge Me

NameDate

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

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

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

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

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

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

  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. Luz says an electron has about the same mass as a proton, since their charges balance. Agree or disagree?

    • Agree: equal charges mean equal mass
    • Disagree: an electron is far lighter
    • Disagree: an electron is heavier
    • Agree: both are particles in one atom

  7. Atomic number, symbol, name. 5 B boron; 6 C carbon; 7 N nitrogen; 8 O oxygen. A carbon atom has 6 protons and 6 neutrons. If it had one more neutron, what would it be, Milo?

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

  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?

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

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

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

  10. A model shows a tiny nucleus and a wide cloud of electrons. Where is most of the mass, Zee?

    • Shared evenly, since everything counts the same
    • Nowhere: atoms are empty
    • In the tiny nucleus
    • In the wide electron cloud
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8th grade Protons, neutrons and electrons worksheet – printable
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About this worksheet

Protons, neutrons and electrons. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can give each particle's charge and place: proton +1 and neutron 0 in the nucleus, electron −1 around it.
  • I can use atomic number = protons, mass number = protons + neutrons, and electrons = protons in a neutral atom.
  • I can say that the protons decide the element and that almost all of the mass is in the nucleus.

Standard: MS-PS1-1

Words to know

proton: A positive particle in the nucleus

neutron: A particle with no charge in the nucleus

electron: A very light negative particle around the nucleus

nucleus: The tiny center of an atom

atomic number: The number of protons; it names the element

mass number: Protons plus neutrons

neutral: Equal positive and negative charges

Common mistakes

Your child added the two numbers instead of subtracting. Remind: the mass number counts protons and neutrons together, so take one away to find the other.

Your child gave the neutron a charge. Say the three together: proton plus, electron minus, neutron neutral (no charge).

Your child put electrons in the nucleus. Draw an atom together: protons and neutrons in the center, electrons around the outside.

Questions parents ask

What is the most common mistake with protons, neutrons and electrons?

Your child added the two numbers instead of subtracting. Remind: the mass number counts protons and neutrons together, so take one away to find the other.

Are these 8th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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