How the periodic table was built and how it is arranged

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   Mendeleev predicted eka-aluminium's atomic mass as 68; gallium's is 69.723. What is the percent difference from the found value, to 0.01%, Ari?

   2.47 %
2. 2.

   Mendeleev predicted eka-aluminium's density as 6 g/cm³; gallium's is 5.91 g/cm³. What is the percent difference from the found value, to 0.01%, Bo?

   1.52 %

3. Read this first

   Use this

   ordered by atomic number

5. 3.

   Using the map, where are the transition metals, Jun?

   • The p block, groups 13–18
   • The s block, groups 1–2
   • The d block, groups 3–12
6. 4.

   Using the map, where is the f block, Kira?

   Use the picture in question 3.

   • At the far left
   • In two rows below
   • At the top right
7. 5.

   Using the map, how many periods does the table have, Luz?

   Use the picture in question 3.

   • 7
   • 4
   • 18
8. 6.

   What sets the order of elements in today's table, Milo?

   • Date of discovery
   • Atomic mass
   • Atomic number
9. 7.

   What does atomic number count, Pia?

   • Isotopes
   • Protons
   • Neutrons
10. 8.

    Why did Mendeleev's gaps matter, Ren?

    • They predicted unfound elements
    • They hid the mistakes in his data
    • They saved space
11. 9.

    What did finding gallium and germanium show, Tala?

    • The table was wrong
    • Elements change over time
    • The table could predict
12. 10.

    How did Mendeleev predict an unfound element's properties, Zee?

    • From its color
    • By guessing, with no data to go on
    • From its neighbors in the table