Chemistry
Assertion (A): Hydrogen is placed in group I.
Reason (R): Hydrogen can gain an electron to achieve noble gas configuration.
- 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 but R is not the correct explanation of A.
Explanation — Hydrogen is placed in Group I with alkali metals because, like them, it has one electron in its outermost shell and forms (H⁺) ions by losing this electron. Although hydrogen can also gain an electron to form the hydride ion (H⁻) similar to halogens. Hence, Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
Related Questions
Assertion (A): In a Dobereiner's triad, the three elements present have the same difference of atomic masses.
Reason (R): Elements in a triad have similar properties.
- 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): Smaller the size of an atom greater is its electronegativity.
Reason (R): Electronegativity is the tendency of an atom to attract shared pair of electrons towards itself in a molecule.
- 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): Atomic size increases along a period.
Reason (R): Effective nuclear charge increases with 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.
Assertion (A): Elements in the same vertical column have similar properties.
Reason (R): Properties depend upon the number of electrons in the valence shell.
- 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.