Advertisements
Advertisements
Question
Why the first ionisation enthalpy of sodium is lower than that of magnesium while its second ionisation enthalpy is higher than that of magnesium?
Solution
The first ionization enthalpy of magnesium is higher than that of Na due to the higher nuclear charge and slightly smaller atomic radius of Mg than Na. After the loss of the first electron, Na+ formed has the electronic configuration of neon (2, 8). The higher stability of the completely filled noble gas configuration leads to a very high second ionization enthalpy for sodium. On the other hand, Mg+ formed after losing the first electron still has one more electron in its outermost (3s) orbital. As a result, the second ionization enthalpy of magnesium is much smaller than that of sodium.
APPEARS IN
RELATED QUESTIONS
Which of the following elements will have the highest electronegativity?
Various successive ionisation enthalpies (in kJ mol-1) of an element are given below.
| IE1 | IE2 | IE3 | IE4 | IE5 |
| 577.5 | 1,810 | 2,750 | 11,580 | 14,820 |
The element is
Which of the following is the second most electronegative element?
IE1 and IE2 of Mg are 179 and 348 kcal mol−1 respectively. The energy required for the reaction \[\ce{Mg -> Mg^2+ + 2e^-}\] is
In a given shell the order of screening effect is
The First ionisation potential of Na, Mg and Si are 496, 737 and 786 kJ mol-1 respectively. The ionisation potential of Al will be closer to
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.
Explain the Pauling method for the determination of ionic radius.
Briefly give the basis for Pauling's scale of electronegativity.
State the trends in the variation of electronegativity in groups and periods.
