Yes, the number of atoms is always a whole number. In chemical reactions and calculations, atoms are considered as discrete units, and you cannot have a fraction or a fraction of an atom. The number of atoms is expressed using integers because it represents a count of individual particles.
The concept of atoms as indivisible units is fundamental to the field of chemistry and is captured by Avogadro's constant, which relates the number of atoms or molecules to the amount of substance. Avogadro's constant, approximately 6.022 × 10^23, represents the number of atoms or molecules in one mole of a substance. It emphasizes that atoms and molecules are discrete entities, and the count is always a whole number multiple of Avogadro's constant.
In practical terms, while atoms can combine in specific ratios to form compounds, the resulting chemical formulas express these ratios as whole numbers. For example, water (H2O) consists of two hydrogen atoms and one oxygen atom, not fractions of atoms. Similarly, in the balanced equation for a chemical reaction, the coefficients in front of the chemical formulas represent whole numbers, indicating the relative number of atoms involved.
In summary, the count of atoms is always considered as a whole number, reflecting the discrete nature of atomic and molecular entities in chemical reactions and calculations.