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8th grade atoms, elements and the periodic table

8th grade (Year 9 in England) · 15 questions · Common Core: NGSS.MS-PS1-1, NGSS.HS-PS1-1, NGSS.HS-PS1-2, NGSS.HS-PS1-8 · England: KS3 Chemistry: Atoms, elements and compounds, KS4 Combined Science: Atomic structure and the periodic table, KS4 Combined Science: Chemical changes

Name

Date

Score/ 15

  1. Question 1

    How many atoms are there altogether in one molecule or formula unit of CaCO₃?

    Answer

  2. Question 2

    The noble gases: which statement is NOT true?

    • A. Noble gases are colourless at room temperature.
    • B. Noble gases form diatomic molecules like Cl₂.
    • C. Neon glows red-orange in electric signs.
    • D. Noble gases exist as single atoms.

  3. Question 3

    How many atoms in total are in one molecule (formula unit) of sulfuric acid, H₂SO₄?

    Answer

  4. Question 4

    The alkali metals: which statement is NOT true?

    • A. Group 1 metals have two outer electrons.
    • B. Alkali metals react with water to make alkaline solutions.
    • C. Alkali metals form ions with a 1+ charge.
    • D. Sodium is less dense than water, so it floats.

  5. Question 5

    Which particle has a charge of +1?

    • A. proton
    • B. neutron
    • C. electron

  6. Question 6

    Hydrogen has atomic number 1. How many neutrons are in the isotope hydrogen-1?

    Answer

  7. Question 7

    Why are alkali metals stored under oil?

    • A. to keep them warm
    • B. to stop them reacting with oxygen and water vapour in the air
    • C. because they are liquids
    • D. to make them shiny

  8. Question 8

    Which particle did James Chadwick discover in 1932?

    • A. the electron
    • B. the photon
    • C. the proton
    • D. the neutron

  9. Question 9

    How many H atoms are shown by 2H₂SO₄?

    Answer

  10. Question 10

    What are isotopes?

    • A. atoms with different numbers of protons
    • B. charged atoms
    • C. atoms of the same element with different numbers of neutrons
    • D. atoms of different elements with the same mass

  11. Question 11

    Atomic structure: which statement is true?

    • A. Electrons are found in the nucleus.
    • B. The plum pudding model is today's accepted model of the atom.
    • C. Most of the mass of an atom is in the nucleus.
    • D. Protons and electrons have the same mass.

  12. Question 12

    Why is helium, not hydrogen, used in party balloons and airships today?

    • A. Helium is denser than air
    • B. Hydrogen is a noble gas
    • C. Helium is cheaper than air
    • D. Helium is less dense than air and does not burn

  13. Question 13

    How many O atoms are in one formula unit of Mg(NO₃)₂?

    Answer

  14. Question 14

    Which noble gas is used for glowing red-orange advertising signs?

    • A. helium
    • B. neon
    • C. argon

  15. Question 15

    Chlorine water is added to potassium bromide solution. Will a reaction happen?

    • A. yes: chlorine displaces bromine
    • B. no reaction

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Answer key: 8th grade atoms, elements and the periodic table

  1. 1. 5

  2. 2. B. Noble gases form diatomic molecules like Cl₂.

  3. 3. 7

  4. 4. A. Group 1 metals have two outer electrons.

  5. 5. A. proton

  6. 6. 0

  7. 7. B. to stop them reacting with oxygen and water vapour in the air

  8. 8. D. the neutron

  9. 9. 4

  10. 10. C. atoms of the same element with different numbers of neutrons

  11. 11. C. Most of the mass of an atom is in the nucleus.

  12. 12. D. Helium is less dense than air and does not burn

  13. 13. 6

  14. 14. B. neon

  15. 15. A. yes: chlorine displaces bromine