Which one of the following is the most characteristic property of an

Which one of the following is the most characteristic property of an element?

[amp_mcq option1=”Density” option2=”Boiling point” option3=”Mass number” option4=”Atomic number” correct=”option4″]

This question was previously asked in

UPSC CDS-1 – 2017

The correct answer is D) Atomic number.

The atomic number (Z) is the number of protons in the nucleus of an atom. This number is unique to each element and determines its chemical properties. For example, any atom with 6 protons is Carbon, and any atom with 8 protons is Oxygen. No two elements have the same atomic number.

Mass number (A) is the total number of protons and neutrons in the nucleus. Isotopes of an element have the same atomic number but different mass numbers (due to different numbers of neutrons). Density and boiling point are physical properties that can vary depending on the specific isotope, physical state, temperature, pressure, and purity of the substance. While characteristic, they are not the fundamental defining property of an element itself.

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