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

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

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Predict a simple reaction from the outer electrons

Grade 10 Science Worksheet - Building Confidence

NameDate

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

  1. Sulfur is in group 16. How many electrons does one sulfur atom gain to reach eight outer electrons, Ari?

  2. Nitrogen is in group 15. How many electrons does one nitrogen atom gain to reach eight outer electrons, Bo?

  3. Chlorine is in group 17. How many electrons does one chlorine atom gain to reach eight outer electrons, Esme?

  4. Aluminum is in group 13. Which ion is it predicted to form, Jun?

    • Al¹³⁺, copying the group number
    • Al³⁻, after gaining 3 electrons
    • Al³⁺, after losing its 3 outer electrons

  5. Sulfur is in group 16. Which ion is it predicted to form, Kira?

    • S²⁺, after losing 2 electrons from its outer shell
    • S²⁻, after gaining 2 electrons to reach eight
    • S⁶⁻, gaining its 6 outer electrons again

  6. Fluorine and iodine each gain 1 electron. Which pulls in an electron more strongly, Noah?

    • Fluorine: its outer shell is closest to the nucleus, so the pull is strongest
    • Both pull equally, since each needs exactly 1 electron
    • Iodine: it has more electrons, so it pulls a new one in harder

  7. Sodium reacts with chlorine in a 1 to 1 pattern. Which other element should react with chlorine the same way, Pia?

    • Aluminum, the next metal along the same row
    • Magnesium, which sits right beside sodium in the same row
    • Potassium, which also has 1 outer electron

  8. Potassium (group 1) combines with sulfur (group 16). Which formula is predicted, Ren?

    • KS, because one of each pairs them
    • KS₂, because the subscripts swap places
    • K₂S, because two K⁺ cancel one S²⁻

  9. Calcium (group 2) combines with chlorine (group 17). Which formula is predicted, Tala?

    • CaCl₂, because one Ca²⁺ needs two Cl⁻
    • CaCl, because one of each pairs them
    • Ca₂Cl, because the subscripts swap places

  10. Lithium (group 1) combines with oxygen (group 16). Which formula is predicted, Zee?

    • Li₂O, because two Li⁺ cancel one O²⁻
    • LiO, because one of each pairs them
    • LiO₂, because the subscripts swap places
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10th grade Predict a simple reaction from the outer electrons worksheet – printable
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About this worksheet

Predict a simple reaction from the outer electrons. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can read outer electrons from the group number (groups 1, 2 and 13 to 18).
  • I can say whether an atom loses or gains electrons, and how many, to reach eight.
  • I can predict the formula and balanced equation when a metal meets a nonmetal: group 1 with 17 gives 1 : 1, group 2 with 17 gives 1 : 2.
  • I can use the same pattern down a group, and for an unknown element.

Standard: HS-PS1-2

Words to know

outer (valence) electrons: Electrons in the outermost shell, shown as dots

ion: An atom that has lost or gained electrons, so it has a charge

octet: Eight outer electrons, a stable arrangement

formula unit: The smallest whole-number ratio of ions in an ionic compound

diatomic: Made of two atoms, as Cl₂, O₂ and F₂ are

Common mistakes

Your child gave the number of outer electrons. A nonmetal gains enough to reach eight, which is 8 minus that count.

Your child added the number of metal atoms and the electrons each loses. The total moved is the atoms times the electrons each loses.

Your child counted oxygen, nitrogen or chlorine atoms. These gases come as two-atom molecules, so each molecule takes twice as many electrons.

Questions parents ask

What is the most common mistake with predict a simple reaction from the outer electrons?

Your child gave the number of outer electrons. A nonmetal gains enough to reach eight, which is 8 minus that count.

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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