10th grade Predict a simple reaction from the outer electrons worksheet

Predict a simple reaction from the outer electrons

Grade 10 Science Worksheet

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

1. 1.

   Aluminum (group 13) reacts with oxygen (group 16) to form Al₂O₃. How many electrons move in all to make one Al₂O₃ unit, Ari?
2. 2.

   Magnesium (group 2) reacts with nitrogen (group 15) to form Mg₃N₂. How many electrons move in all to make one Mg₃N₂ unit, Bo?
3. 3.

   Sodium (group 1) reacts with sulfur (group 16) to form Na₂S. How many electrons move in all to make one Na₂S unit, Esme?
4. 4.

   Aluminum (group 13) combines with oxygen (group 16). Which formula is predicted, Jun?

   • Al₃O₂, because the subscripts swap places
   • AlO, because one aluminum atom pairs with one oxygen atom
   • Al₂O₃, because two Al³⁺ (+6) cancel three O²⁻ (−6)
5. 5.

   Magnesium (group 2) combines with nitrogen (group 15). Which formula is predicted, Kira?

   • MgN, because one magnesium atom pairs with one nitrogen atom
   • Mg₂N₃, because the subscripts swap places
   • Mg₃N₂, because three Mg²⁺ (+6) cancel two N³⁻ (−6)
6. 6.

   Which balanced equation shows aluminum burning in oxygen gas, Milo?

   • 2 Al + O₂ → 2 AlO, with one Al for each O
   • 2 Al + 3 O₂ → 2 AlO₃, with 3 oxygen in each product
   • 4 Al + 3 O₂ → 2 Al₂O₃, using Al³⁺ and O²⁻
7. 7.

   Which balanced equation shows magnesium reacting with nitrogen gas, Noah?

   • 2 Mg + N₂ → 2 MgN, with one Mg for each N
   • Mg + N₂ → MgN₂, with N₂ moved into the product
   • 3 Mg + N₂ → Mg₃N₂, using Mg²⁺ and N³⁻

8. Read this first

   Group 1 metals (real data, rounded)

   element	metallic radius (pm)	first ionization energy (kJ/mol)
   lithium	152	520
   sodium	186	496
   potassium	227	419
   rubidium	248	403

9. 8.

   Ren reads the table. Which statement about the group 1 metals is best supported?

   • Reactivity stays the same down the group, since each metal has one outer electron
   • Reactivity falls down the group, because bigger atoms hold their outer electron more tightly
   • Down the group the outer electron is lost more easily, so reactivity should rise

10. Halogens (real data, rounded)

    halogen	electronegativity
    fluorine	3.98
    chlorine	3.16
    bromine	2.96
    iodine	2.66

11. 9.

    Using the table, which pair reacts: chlorine gas with sodium bromide solution, or iodine with sodium bromide solution, Tala?

    • Iodine with sodium bromide: iodine is larger, so it takes electrons more easily
    • Both react, since the halogens each gain one electron
    • Chlorine with sodium bromide: chlorine pulls electrons harder (3.16 to 2.96)
12. 10.

    Strontium is in group 2, below calcium. Which equation predicts its reaction with oxygen gas, Zee?

    • 2 Sr + O₂ → 2 SrO
    • Sr + O₂ → SrO₂
    • 4 Sr + O₂ → 2 Sr₂O