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10th grade Atomic and ionic size across the periodic table worksheet

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Atomic and ionic size across the periodic table

Grade 10 Science Worksheet - Challenge Me

NameDate

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

  1. Lithium's radius is 145 pm and sodium's is 180 pm (Slater). By what percent does radius grow from lithium to sodium, to 0.01%, Ari?

  2. Sodium's radius is 180 pm and potassium's is 220 pm (Slater). By what percent does radius grow from sodium to potassium, to 0.01%, Bo?

  3. Potassium's radius is 220 pm and rubidium's is 235 pm (Slater). By what percent does radius grow from potassium to rubidium, to 0.01%, Esme?

  4. Read this first

    Ionic radii in pm (Shannon 1976, six-coordinate) (Shannon 1976)

    ionelectronsradius (pm)
    O²⁻10140
    F⁻10133
    Na⁺10102
    Mg²⁺1072
    Cl⁻18181
    K⁺18138
  5. Using the table, why does size fall from O²⁻ to F⁻ to Na⁺ to Mg²⁺, Jun?

    • More protons pull the same 10 electrons
    • They each have fewer electrons, step by step
    • They lose shells each step
  6. Using the table, which 10-electron ion is largest, Kira?

    • O²⁻
    • Mg²⁺
    • Na⁺
  7. Using the table, K⁺ and Cl⁻ both have 18 electrons. Why is K⁺ smaller, Luz?

    • It has more electrons
    • It has fewer shells
    • It has more protons
  8. Milo says chlorine is bigger than sodium because it has more electrons. Agree or disagree?

    • Disagree: more protons pull it smaller
    • Agree: more electrons take up more room
    • Agree: heavier atoms are wider
  9. Which lists potassium, sodium and magnesium from largest to smallest, Ren?

    • Sodium, potassium, magnesium
    • Magnesium, sodium, potassium
    • Potassium, sodium, magnesium
  10. Which is larger, chlorine or iodine, Tala?

    • Chlorine
    • Iodine
    • They are equal
  11. Where on the table are the largest atoms, Zee?

    • Top left
    • Bottom left
    • Top right
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10th grade Atomic and ionic size across the periodic table worksheet – printable
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About this worksheet

Atomic and ionic size across the periodic table. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can say that atomic radius shrinks across a period (more protons pull the same shell) and grows down a group (more shells).
  • I can say that positive ions are smaller than their atoms and negative ions larger.
  • I can compare ions with the same number of electrons: more protons, smaller ion.
  • I can read radius tables and work out differences, ratios and percent growth.

Standard: HS-PS1-1

Words to know

atomic radius: Half the distance between two bonded nuclei of an element

ionic radius: The size of an ion in a crystal

cation: A positive ion, smaller than its atom

anion: A negative ion, larger than its atom

picometer (pm): 10⁻¹² m

Common mistakes

Your child added the radii. How much smaller one atom is than another is a difference: subtract.

Your child divided the smaller ion by the larger. To say how many times larger, divide the larger radius by the smaller.

Your child divided by the new radius. Percent growth compares with the starting size: (new − old) ÷ old × 100.

Questions parents ask

What is the most common mistake with atomic and ionic size across the periodic table?

Your child added the radii. How much smaller one atom is than another is a difference: subtract.

Are these 10th 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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