Question

Pair of isobar is : (a) \({ }_{6} \mathrm{C}^{13},{ }_{7} \mathrm{~N}^{13}\) (b) \({ }_{6} \mathrm{C}^{13},{ }_{7} \mathrm{~N}^{14}\) (c) \({ }_{6} \mathrm{C}^{14} ;{ }_{8} \mathrm{~N}^{15}\) (d) none of these

Short answer

The correct pair of isobars is (a) \( _{6}C^{13}\), \( _{7}N^{13}\) as both have the mass number 13.

Step-by-step solution

Understand Isobars

Isobars are atoms of different chemical elements that have the same number of nucleons, which means they have the same mass number (A). The mass number is equal to the sum of the number of protons and neutrons in the nucleus.

Check mass numbers of the given pairs

Determine the mass number of each element in each pair by looking at the upper right superscript. The pairs of isobars will have the same mass numbers.

Identify the Pair of Isobars

Compare the mass numbers across all options to identify the pair that has the same mass number for both elements in the pair.

Key concepts

Mass Number

The mass number, often denoted by the letter 'A', is one of the fundamental identifiers of an element. It represents the total number of protons and neutrons in an atom's nucleus. These particles are collectively known as nucleons. Since electrons have negligible mass compared to protons and neutrons, they do not contribute significantly to the atom's mass number.

Understanding the mass number is crucial when exploring isotopes and isobars. For instance, in an isobar scenario, even though two atoms may belong to different elements (having a different number of protons), they can have the same mass number. This occurs when the difference in proton count is compensated for by an inverse difference in the neutron count. Thus, mass number serves as a pivotal element in recognizing isobars.

Nucleons

Nucleons are the components of an atom's nucleus, encompassing both protons and neutrons. The term 'nucleon' is a collective reference to these two types of particles. Protons are positively charged particles, while neutrons carry no charge. The number of protons (atomic number) determines the chemical properties of an element, while the number of neutrons can vary even within atoms of the same element, resulting in different isotopes.

Nucleons are significant due to their role in the atomic mass number—they are the building blocks that comprise the mass number. An understanding of nucleons is vital when discussing nuclear reactions, radioactive decay, and isobars, as all these processes involve changes in or characteristics of the nucleus.

Atomic Number

The atomic number, indicated by the symbol 'Z', identifies the element on the periodic table. It corresponds to the number of protons found in the nucleus of an atom and hence is unique for each element. Since electrons equal the number of protons in a neutral atom, the atomic number also tells us the number of electrons in that state.

An atom's chemical behavior is defined by its atomic number, as it determines the element's position in the periodic table and its electronic configuration. Unlike the mass number, the atomic number doesn't change during typical chemical reactions. It can only change in nuclear reactions when the identity of the element itself changes. In the context of isobars, it is this atomic number that differs between two elements having the same mass number.