Democritus and the Theory of Atoms

Which of the following statements is true about elements?

• Each element is made of a mixture of different kinds of atoms.

• Each element is made of its own particular kind of atom.

• Elements are made of molecules.

• Elements are made of compounds.

Which of the following is the chemical symbol for gold?

• C

• O

• Au

• Ag

Where can elements be found organized by their atomic number and common features?

• The chemical symbol chart

• The periodic table

• The atomic number list

• The element group chart

What does the atomic number of an element represent?

• The number of neutrons

• The number of protons

• The number of electrons

• The atomic mass

What is the atomic number of Neon (Ne)?

• 8

• 10

• 12

• 20

What is the atomic mass of Neon (Ne)?

• 10.1797

• 15.1797

• 20.1797

• 25.1797

What is a compound?

• A substance made of only one type of element.

• A substance in which the atom(s) of one element are bonded to the atom(s) of another element.

• A mixture of different elements that are not bonded together.

• A single element in its pure form.

Which of the following is an example of a compound?

• Oxygen gas

• Sodium

• Salt

• Chlorine

What is a molecule?

• A single atom

• A group of two or more atoms that stick (bond) together

• A group of two or more electrons

• A single electron

What can molecules be composed of?

• Only pure elements

• Only compounds

• Pure elements or compounds

• Only gases