Which one of the following statements is not correct ?
[amp_mcq option1=”Elements are defined by the number of protons they possess.” option2=”Isobars are atoms having the same atomic number but different mass number.” option3=”The mass number of an atom is equal to the number of nucleons in its nucleus.” option4=”Valency is the combining capacity of an atom.” correct=”option2″]
This question was previously asked in
UPSC CDS-2 – 2019
– Isobars are atoms of different elements that have the same mass number but different atomic numbers.
– Isotopes are atoms of the same element that have the same atomic number but different mass numbers.
– The mass number is the total number of protons and neutrons (nucleons) in an atom’s nucleus.
– Valency refers to the combining capacity of an atom, determining how it forms chemical bonds.