STD 11 - 3. Classification of elements and periodicity in properties — NEET STD 11 Science — Question

(Density of water $= 1\,gm/ml$ )

$A$. $\mathrm{Be} \rightarrow \mathrm{Be}^{-}$

$B$. $\mathrm{N} \rightarrow \mathrm{N}^{-}$

$C$. $\mathrm{O} \rightarrow \mathrm{O}^{2-}$

$D$. $\mathrm{Na} \rightarrow \mathrm{Na}^{-}$

$E$. $\mathrm{Al} \rightarrow \mathrm{Al}^{-}$

Choose the most appropriate answer from the options given below :

$(I)$ Only compounds with chiral centers can be optically active

$(II)$ Absence of elements of symmetry is the reason for a molecule's optical activity

$(II)$ All organic compounds contain carbon & hydrogen

$(IV)$ Different cannonical forms of a molecule represent the actual structures of a molecule which has resonace in it