Question

counting elements and atoms
atoms
•the smallest part of a chemical element
•found on the periodic table
•combining atoms creates molecules.
how many atoms are in the molecule of an element?
how many atoms are in the molecule of a compound?
molecule of an element (same kind of atoms)
compounds are molecules combining two or more elements (different kinds of atoms)

Explanation:

Step1: Define molecule of an element

A molecule of an element consists of the same - kind of atoms. The simplest case is a single - atom element (e.g., noble gases like He, Ne), where there is 1 atom in the molecule. But for di - atomic elements like $H_2$, $O_2$, $N_2$, etc., there are 2 atoms in the molecule. In general, the number of atoms in a molecule of an element can vary, but for the most common di - atomic elements, there are 2 atoms.

Step2: Define molecule of a compound

A compound is a molecule combining two or more elements (different kinds of atoms). For example, in a water molecule $H_2O$, there are 3 atoms (2 hydrogen atoms and 1 oxygen atom). In carbon dioxide $CO_2$, there are 3 atoms (1 carbon atom and 2 oxygen atoms). So, the number of atoms in a molecule of a compound depends on the chemical formula of the compound and can be 2 or more.

Answer:

The number of atoms in a molecule of an element can be 1 (for single - atom elements) or 2 (for common di - atomic elements) or more. The number of atoms in a molecule of a compound is 2 or more.