Question 52

The order of elements in the periodic table is determined by the number of protons.

The arrangement of elements in the periodic table is based on the increasing atomic number, which is the number of protons in an atom's nucleus.

A) The number of valence electrons

While the number of valence electrons is crucial for determining chemical properties and reactivity of elements, it does not dictate the order of elements in the periodic table. Elements are organized by their atomic number, not by their electron configuration.

B) The number of electron shells

The number of electron shells contributes to an element's placement in terms of periods or rows in the periodic table, but it is not the primary criterion for the order of elements. The order is fundamentally based on the atomic number, which reflects the number of protons.

C) The number of protons

The number of protons, or atomic number, is the key factor that determines the order of elements in the periodic table. Each element is uniquely defined by its number of protons, and they are arranged in ascending order based on this value.

D) The number of neutrons

The number of neutrons does not influence the order of elements in the periodic table. Neutrons contribute to the mass of an atom and can affect isotopes, but the organization of the table relies solely on the atomic number, which is dictated by protons.

Conclusion

The correct answer is C, as the number of protons directly determines the atomic number and thus the order of elements in the periodic table. Options A, B, and D, while related to atomic structure, do not influence the arrangement of elements in this systematic way, confirming that only the number of protons is relevant for this specific organization.