Question

i. an atom is the smallest unit of an element and a molecule is made up of two or more atoms chemically bonded together.
ii. an atom is indivisible and a molecule can be broken down into atoms.
iii. an atom is the smallest unit bonded together and a molecule is made up of elements.
iv. an element is the smallest unit of an atom and a molecule is made up of two or more metal and non - metal atoms chemically bonded together.
which conclusion(s) best elaborate on the difference(s) between an atom and a molecule?
a i & ii
b ii & iii
c iii & iv
d iv & i

Explanation:

• Statement I: An atom is the smallest unit of an element. A molecule is made up of two or more atoms chemically bonded together. This is a correct description of the difference.
• Statement II: Atoms are the basic building blocks and are indivisible in chemical reactions (in the context of Dalton's atomic theory, which is a fundamental concept for this level of study). Molecules can be broken down into atoms. This is also a correct description.
• Statement III: An atom is not “the smallest unit bonded together”. A molecule is made up of atoms, not just elements in a non - specific way. So this statement is incorrect.
• Statement IV: An atom is the smallest unit of an element, not the other way around. Also, a molecule can be made up of non - metal atoms (e.g., \(O_2\)) or metal and non - metal atoms (e.g., \(NaCl\)), but the first part of the statement is wrong.

Answer:

A. I & II