What number uniquely identifies an element?
Understand the Problem
The question is asking for a number that serves as a unique identifier for each element in the periodic table, which refers to the atomic number. Each element has a distinct atomic number that corresponds to the number of protons in its nucleus.
Answer
atomic number
The number that uniquely identifies an element is the atomic number (Z).
Answer for screen readers
The number that uniquely identifies an element is the atomic number (Z).
More Information
The atomic number is unique for each element because it is equal to the number of protons in the nucleus of an atom. This property distinguishes one element from another.
Tips
A common mistake is to confuse the atomic number with the mass number, which includes both protons and neutrons.
Sources
- The web page with info on - Energy Education - energyeducation.ca
- Atomic number - Wikipedia - en.wikipedia.org
- Atomic Number - Chemistry LibreTexts - chem.libretexts.org