The Periodic Table · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

The periodic table: periods, groups, and Mendeleev

Science · Matter & Materials · ages 11-12
Name ______________________   Date ____________

  1. What do we call a column in the periodic table?

    • A period
    • A group
    • An element

  2. In the periodic table, what do we call a row?

    • A period
    • A group
    • An isotope

  3. Elements in the same group have similar chemical properties.

    Circle one:   True   False

  4. Sodium and potassium are in the same group. How do they react with water?

    NaK
    • They react in a similar way
    • They react in opposite ways
    • They do not react at all

  5. Where are most metals found on the periodic table?

    • Top right corner
    • Spread evenly all over
    • Left and middle

  6. Mendeleev arranged elements in order of their ___ and left gaps for elements not yet discovered.

    • alphabetical order of their names
    • atomic weight
    • how common they are

  7. Mendeleev's table was useful only because it looked neat, not because it predicted anything new.

    Circle one:   True   False

  8. A newly found element reacts almost exactly like sodium and potassium. Where should chemists expect to place it?

    • In a totally different group
    • In the top right corner
    • In the same group as sodium and potassium
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Answer key

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

The periodic table: periods, groups, and Mendeleev W1-mt_wfEfQuHOG--s1

  1. A group · Columns are called groups. Rows are called periods.
  2. A period · Rows across the table are called periods. Columns are called groups.
  3. True · Elements in a group react in similar ways, which is why chemists group them together.
  4. They react in a similar way · Same group means similar properties, so both react with water in the same way.
  5. Left and middle · Most elements are metals, and they fill the left and middle of the table. Non-metals are mostly in the top right.
  6. atomic weight · He ordered elements by atomic weight. The gaps he left were later filled by real elements matching his predictions.
  7. False · Mendeleev's table left gaps for missing elements and predicted their properties correctly, which is why other chemists trusted it, not just because it looked tidy.
  8. In the same group as sodium and potassium · Elements that react alike usually belong in the same group, so that is the best place to look.
Worksheet · LightMySky