Atomic and ionic size across the periodic table

Answer Key - Grade 10 Science Worksheet - Building Confidence

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

1. 1.

   Sodium's atomic radius is 180 pm and magnesium's is 150 pm (Slater). How many pm smaller is magnesium, Ari?

   30 pm
2. 2.

   Magnesium's atomic radius is 150 pm and aluminum's is 125 pm (Slater). How many pm smaller is aluminum, Bo?

   25 pm
3. 3.

   Aluminum's atomic radius is 125 pm and silicon's is 110 pm (Slater). How many pm smaller is silicon, Esme?

   15 pm
5. 4.

   Using the table, which atom is largest, Jun?

   • Cesium
   • Silicon
   • Sodium
6. 5.

   Using the table, what happens to radius across period 3, Kira?

   Use the picture in question 4.

   • It shrinks
   • It grows
   • It stays the same
7. 6.

   Why do atoms get smaller across a period, Milo?

   • They lose shells
   • More protons pull the same shell in
   • They gain electrons and swell outward
8. 7.

   Chlorine and sodium both use shell 3. Why is chlorine smaller, Noah?

   • Its extra electrons make it bigger
   • It has fewer shells
   • Its 17 protons pull harder
9. 8.

   How many shells do the atoms across period 3 have, Pia?

   • One more each step
   • Eight each
   • Three each
10. 9.

    Why is potassium larger than sodium, Tala?

    • It has one more shell
    • It is a gas
    • It has fewer protons inside
11. 10.

    In a larger atom, where are the outer electrons, Zee?

    • Inside the nucleus
    • Closer to the nucleus
    • Farther from the nucleus