Chemistry
Assertion (A): The atomic mass of an element is mainly the mass of its nucleus.
Reason (R): The nucleus of an element contains neutrons and protons and the electrons have a negligible mass.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Answer
Both A and R are true and R is the correct explanation of A.
Explanation — Mass number of an element is the total number of protons and neutrons present in its nucleus. Hence, the asertion (A) is true.
Protons and neutrons each have a mass of about 1 atomic mass unit (amu). Electrons have a mass approximately 1/1836 that of a proton, extremely small and usually neglected in atomic mass calculations. Hence reason (R) is true and reason (R) is the correct explanation of assertion (A).
Related Questions
Select the correct statement(s) for the diagram shown below.
P — Mg looses electrons and undergoes reduction.
Q — Cl gains electrons and undergoes reduction.
R — Mg looses electrons and undergoes oxidation.
- Only P
- Only Q
- Only R
- Both Q and R
Select the correct statement(s) for the diagram shown below.
P — One atom of carbon transfers one electron to each chlorine atom.
Q — One atom of carbon shares four electron pairs, one with each of the four atoms of chlorine.
R — Carbon atom attains neon configuration and chlorine attains argon configuration after the combination.
- Only P
- Only Q
- Only R
- Both Q and R
Assertion (A): An alpha particle is the same as a Helium nucleus.
Reason (R): An alpha particle does not have any electron.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): Isotopes of an element have similar chemical properties.
Reason (R): Isotopes of an element have the same atomic number.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.