Elements arranged by increasing atomic number form what?

• A. Isotopes
• B. Periodic table
• C. Atomic number
• D. Chemical formula

Answer: (B)

Ordering elements by increasing atomic number reveals the recurring patterns in their properties and is what the periodic table captures. The atomic number counts protons, so as you go from one element to the next, the electron configuration changes in a regular way, causing trends in reactivity and other traits. This systematic organization into a chart—the periodic table—shows elements in columns with similar chemical behavior and across rows that reflect electron-shell filling.

Isotopes are simply the same element with different numbers of neutrons, so they share the same atomic number and wouldn’t produce a new, distinct arrangement by proton count. A chemical formula describes how elements combine in compounds, not a listing of elements by atomic number. And atomic number is the factor used to order the elements; the arrangement that results from this order is the periodic table.