HSC Science Class 11 - Tamil Nadu Board of Secondary Education Question Bank Solutions for Chemistry

Is the definition given below for ionisation enthalpy is correct?

"Ionisation enthalpy is defined as the energy required to remove the most loosely bound electron from the valence shell of an atom"

Magnesium loses electrons successively to form Mg⁺, Mg²⁺ and Mg³⁺ ions. Which step will have the highest ionisation energy and why?

Define electronegativity.

How would you explain the fact that the second ionisation potential is always higher than the first ionisation potential?

Energy of an electron in the ground state of the hydrogen atom is −2.18 × 10⁻¹⁸ J. Calculate the ionisation enthalpy of atomic hydrogen in terms of kJ mol⁻¹.

In what period and group will an element with Z = 118 will be present?

Explain the Pauling method for the determination of ionic radius.

Explain the periodic trend of ionisation potential.

Why the first ionisation enthalpy of sodium is lower than that of magnesium while its second ionisation enthalpy is higher than that of magnesium?

By using Pauling's method calculate the ionic radii of K⁺ and Cl⁻ ions in the potassium chloride crystal. Given that `"d"_("K"^+) - "Cl"^-` = 3.14 Å

Explain the following, give an appropriate reason.

Ionisation potential of N is greater than that of O

Explain the following, give an appropriate reason.

First ionisation potential of the C-atom is greater than that of the B atom, whereas the reverse is true is for the second ionisation potential.

Explain the following, give an appropriate reason.

The electron affinity values of Be and Mg are almost zero and those of N (0.02 eV) and P (0.80 eV) are very low.

Explain the following, give an appropriate reason.

The formation of \[\ce{F^-_{(g)}}\] from \[\ce{F_{(g)}}\] is exothermic while that of \[\ce{O^2-_{(g)}}\] from \[\ce{O_{(g)}}\] is endothermic.

What is the screening effect?

Briefly give the basis for Pauling's scale of electronegativity.

State the trends in the variation of electronegativity in groups and periods.

Heavy water is used as

Do you think that heavy water can be used for drinking purposes?

Give the uses of heavy water.