Question

How do molecules of elements and molecules of compounds differ? In what ways are they similar?

a) Molecules of elements have only one type of atom; molecules of compounds have different types of atoms.
b) Molecules of elements have variable compositions; molecules of compounds have fixed compositions.
c) Molecules of elements undergo chemical reactions; molecules of compounds undergo physical changes.
d) Molecules of elements and compounds are similar in all aspects.

Answer 1

Molecules of elements contain only one type of atom, while molecules of compounds have two or more types. Both types of molecules are groups of atoms bonded together. Compounds have a fixed composition and distinct properties compared to elements and mixtures. The correct option is A.

Step-by-step explanation:

Molecules of elements differ from molecules of compounds mainly in the types of atoms they contain. Molecules of elements contain only one type of atom, while molecules of compounds consist of two or more different types of atoms chemically bonded together.

For example, a molecule of oxygen (O2) is an element because it contains two oxygen atoms, whereas water (H2O) is a compound consisting of hydrogen and oxygen atoms.

Despite their differences, molecules of elements and compounds are similar in that they both represent entities made of atoms bonded together. Be it a pure element like nitrogen (N2) with identical atoms, or a diverse compound like carbon dioxide (CO2) with different atoms, they all exhibit the fundamental characteristic of being the smallest particle still retaining chemical identity.

Compounds also have a fixed composition; the atoms within a compound are always present in a definite and constant ratio. This is unlike mixtures, where the proportions of constituents can vary. The strict ratio for compounds leads to a consistent set of chemical and physical properties, distinguishing them further from elements and mixtures.