Question

1. which of the following is not a true statement?

a. two or more atoms held together with bonds make up a molecule.
b. pure substances are made of only one type of atom.
c. at least two types of atoms are required to make a compound.
d. mixtures can be made of two elements, two compounds or an element and a compound.

Explanation:

• Option a: A molecule is indeed formed by two or more atoms held together by bonds.
• Option b: Pure substances can be elements (made of one - type of atom) or compounds (made of more than one type of atom), so this statement is false as pure substances aren't always just one - type of atom.
• Option c: A compound is defined as a substance made up of at least two different types of atoms.
• Option d: Mixtures can be combinations of two elements, two compounds, or an element and a compound.

Answer:

B. Pure substances are made of only one type of atom.