NEET Classification of Elements and Periodicity in Properties — Set 20

Question 1

Which group 16 element forms a hydride with the lowest boiling point?

Accepted Answer

Boiling points of group 16 hydrides increase with molecular weight, except for $\ce{H2O}$ (hydrogen bonding). $\ce{H2S}$ has the lowest boiling point among $\ce{H2O}$, $\ce{H2S}$, $\ce{H2Se}$, and $\ce{H2Te}$ due to weak intermolecular forces.

Question 2

Which element in the fourth period has the highest third ionization enthalpy?

Accepted Answer

Third ionization enthalpy peaks when removing an electron from a noble gas-like $\ce{X^2+}$ ion. Ca (after losing two electrons, becomes $\ce{Ca^2+}$ with $1s^2 2s^2 2p^6 3s^2 3p^6$) has the highest value.

Question 3

Which element was predicted as Eka-silicon by Mendeleev?

Accepted Answer

Mendeleev predicted Eka-silicon below Si, later identified as Germanium (Ge), matching its properties like oxide formula $\ce{GeO2}$.

NEET Chemistry: Classification of Elements and Periodicity in Properties — Practice Set 20

Q1. Which group 16 element forms a hydride with the lowest boiling point?

Q2. Which element in the fourth period has the highest third ionization enthalpy?

Q3. Which element was predicted as Eka-silicon by Mendeleev?

Q4. Which of the following is a metalloid?

Q5. Which of the following is an s-block element?

Q6. Arrange the following elements in order of decreasing second ionization enthalpy: Li, Be, B, C.

Q7. Which element in group 2 has the highest second ionization enthalpy?

Q8. Which element in the fifth period has the highest sixth ionization enthalpy?

Q9. Which of the following elements exhibits a diagonal relationship with Be?

Q10. Which element in group 16 has the lowest first ionization enthalpy?