To find the total number of electrons in one molecule of carbon dioxide (CO₂), we need to consider the atomic structure of the atoms involved in the molecule. Carbon dioxide consists of one carbon atom and two oxygen atoms.

Carbon (C) has an atomic number of 6, which means a neutral carbon atom has 6 electrons. Oxygen (O) has an atomic number of 8, meaning a neutral oxygen atom has 8 electrons.

Therefore, the total number of electrons in a CO₂ molecule can be calculated as follows:

Number of electrons in carbon = 6

Number of electrons in one oxygen = 8

So, number of electrons in two oxygens = 2 x 8 = 16

Total number of electrons in CO₂ = 6 (from C) + 16 (from 2O) = 22

So, the correct answer is Option A: 22