Atomic and ionic size across the periodic table

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   Cl⁻ has a radius of 181 pm and Na⁺ of 102 pm (Shannon). How many times larger is Cl⁻, to 0.01, Ari?

   1.77 times
2. 2.

   O²⁻ has a radius of 140 pm and Mg²⁺ of 72 pm (Shannon). How many times larger is O²⁻, to 0.01, Bo?

   1.94 times
3. 3.

   Cl⁻ has a radius of 181 pm and K⁺ of 138 pm (Shannon). How many times larger is Cl⁻, to 0.01, Esme?

   1.31 times

4. Read this first

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

   ion	electrons	radius (pm)
   O²⁻	10	140
   F⁻	10	133
   Na⁺	10	102
   Mg²⁺	10	72
   Cl⁻	18	181
   K⁺	18	138

5. 4.

   Using the table, which ion is smallest, Jun?

   • O²⁻
   • Cl⁻
   • Mg²⁺
6. 5.

   Using the table, how does Na⁺ compare in size with F⁻, Luz?

   • Na⁺ is larger
   • Na⁺ is smaller
   • They are equal
7. 6.

   Why is Na⁺ much smaller than a sodium atom, Milo?

   • It has gained a shell
   • It has lost its outer shell
   • It has lost protons
8. 7.

   Which is smaller, a magnesium atom or Mg²⁺, Pia?

   • The magnesium atom
   • Mg²⁺
   • They are the same size
9. 8.

   Why is Cl⁻ larger than a chlorine atom, Ren?

   • It has gained a proton
   • Its extra electron adds repulsion
   • It has lost a shell
10. 9.

    What happens to an atom's size when it gains electrons, Tala?

    • It disappears
    • It gets larger
    • It gets smaller
11. 10.

    Which is larger, an oxygen atom or O²⁻, Zee?

    • They are the same size
    • The oxygen atom
    • O²⁻