Main-Group Chemistry: What Changes Down a p-Block Group · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

What changes as you go down a p-block group

Science · Chemistry · ages 19-20
Name ______________________   Date ____________

  1. Why do elements in one group form similar compounds?

    • They have the same atomic number
    • They sit at the same distance from the nucleus
    • They share the same count of outer electrons

  2. An element sits in group 15 of the periodic table. How many valence electrons does it have?

    • Five
    • Three
    • Eight

  3. Second-row elements such as carbon and nitrogen can never hold more than eight electrons in bonds. True or false?

    Circle one:   True   False

  4. Lead prefers the +2 state over the +4 state. How many fewer electrons does it lose in its preferred state? Give a number.

    Answer: ______________

  5. Phosphorus bonds to five chlorine atoms to make PCl5. What does this prove about phosphorus?

    • It has fewer outer electrons than carbon
    • It can hold more than eight electrons in bonds
    • Its bonds are shorter and stronger

  6. Thallium is a heavy p-block element. Which oxidation state does it prefer?

    • Tl(I)
    • Tl(III)
    • Tl(V)

  7. You compare hydrides down group 15, from NH3 to BiH3. How do the bonds change and why?

    • Bonds get shorter and stronger, since the nucleus pulls harder
    • Bonds get longer and weaker, since outer electrons sit farther out
    • Bond strength stays the same, since the outer count is unchanged

  8. Lee claims carbon can make CCl5 just like phosphorus makes PCl5. What is wrong with the claim?

    • Carbon has too few outer electrons
    • Carbon sits too close to the nucleus
    • Carbon is capped at eight electrons
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Answer key

For grown-ups. Fold this page away before handing over the rest.

What changes as you go down a p-block group W1-mt_wq15-pBrI5-s1

  1. They share the same count of outer electrons · One group means one shared outer electron count, and that count drives similar reactions.
  2. Five · Group 15 means five outer electrons, since groups 13 to 18 run from three up to eight.
  3. True · The second row fills only the 2s and 2p orbitals, which hold eight electrons at most.
  4. 2 · Lead prefers state +2 over +4, and 4 minus 2 equals 2.
  5. It can hold more than eight electrons in bonds · Phosphorus sits in the third row, where atoms can exceed eight electrons.
  6. Tl(I) · The outer s pair stays put, so thallium keeps one bond worth of electrons and picks Tl(I).
  7. Bonds get longer and weaker, since outer electrons sit farther out · Each row down adds a shell, so overlap worsens and the bond weakens even though the count matches.
  8. Carbon is capped at eight electrons · CCl5 would need more than eight electrons around carbon, which the 2s and 2p orbitals cannot hold.
Worksheet · LightMySky