Atoms and elements

Question

a)  An atom is made up of ...

    • ions, protons, and electrons.

    • neutrons, electrons, and molecules.

    • molecules, neutrons, and ions.

    • electrons, neutrons, and protons.

Question

b)  Which of the following substances are all elements? 

    • Carbon dioxide, iron, salt.

    • Water, air, oxygen.

    • Iron, sulfur, oxygen.

    • Air, oxygen, nitrogen.

Question

c)  The element carbon has an atomic number of 6. This number refers to ...

    • the number of protons.

    • how reactive the atom is.

    • the number of protons and neutrons.

    • how heavy an atom of carbon is.