Composition and size of the nucleus; isotopes, isobars and isotones — NEET & JEE Questions

Question 1 · difficulty L1 · recall

The atomic number Z equals the number of

• A. protons in the nucleus
• B. neutrons only
• C. nucleons minus electrons
• D. protons plus neutrons

Question 2 · difficulty L1 · understanding

The mass number A equals

• A. number of protons only
• B. number of protons plus neutrons
• C. number of neutrons only
• D. number of electrons plus protons in every ion

Question 3 · difficulty L2 · understanding

Isotopes are nuclei with

• A. same A but different Z
• B. same neutron number but different Z
• C. same Z but different A
• D. different Z and same electron count only

Question 4 · difficulty L2 · application

Isobars are nuclei with

• A. same Z and different A
• B. same neutron number only
• C. same binding energy necessarily
• D. same A but different Z

Question 5 · difficulty L2 · understanding

Which statement correctly distinguishes isotopes and isobars?

• A. Isotopes have the same atomic number but different mass numbers; isobars have the same mass number but different atomic numbers
• B. Isotopes have the same mass number; isobars have the same atomic number
• C. Both have identical Z and A
• D. Isotopes differ only in electron charge

Question 6 · difficulty L3 · application

Isotones have

• A. the same neutron number
• B. the same proton number
• C. the same mass number only
• D. the same charge and mass always

Question 7 · difficulty L3 · application

Nuclear radius is approximately described by

• A. R=R0 A
• B. R=R0 A^(1/3)
• C. R=R0/A
• D. R=R0 A²

Question 8 · difficulty L3 · application

Nuclei $^{14}_{6}C$ and $^{15}_{7}N$ each contain how many neutrons, and what relation do they illustrate?

• A. 8 neutrons each; isotones
• B. 7 neutrons each; isotopes
• C. 14 neutrons each; isobars
• D. 6 neutrons each; isotones

Question 9 · difficulty L3 · application

Using $R=R_0A^{1/3}$, if the mass number of a nucleus increases by a factor of 8, its radius changes by a factor of

• A. 2
• B. 8
• C. 4
• D. 1/2

Question 10 · difficulty L4 · analysis

If mass number increases by a factor of 8, nuclear radius increases by a factor of

• A. 8
• B. 4
• C. 2
• D. sqrt(8)