Advertisements
Advertisements
Question
How does ionization enthalpy vary down the group and across a period?
Solution
- Variation of ionization enthalpy down the group: On moving down the group, the ionization enthalpy decreases. This is because the electron is to be removed from the larger valence shell. Screening due to core electrons goes on increasing and the effective nuclear charge decreases down the group. As a result, the removal of the outer electron becomes easier down the group.
- Variation of ionization enthalpy across a period: The screening effect is the same while the effective nuclear charge increases across a period. As a result, the outer electron is held more tightly, and hence, the ionization enthalpy increases across a period. Therefore, the alkali metal shows the lowest first ionization enthalpy while the inert gas shows the highest first ionization enthalpy across a period.
APPEARS IN
RELATED QUESTIONS
Explain the following.
The atomic radii of Cl, I, and Br are 99, 133, and 114 pm, respectively.
Explain the following.
The ionic radii of FΘ and Na⊕ are 133 and 98 pm, respectively.
Explain the following.
13Al is a metal, 14Si is a metalloid and 15P is a nonmetal.
Answer the following.
Ionization enthalpy of Li is 520 kJ mol-1 while that of F is 1681 kJ mol-1. Explain.
Answer the following.
Why the second ionization enthalpy is greater than the first ionization enthalpy?
Answer the following.
Why the elements belonging to the same group do have similar chemical properties?
Choose the correct option.
Consider the elements B, Al, Mg, and K predict the correct order of metallic character:
Choose the correct option.
If the valence shell electronic configuration is ns2np5, the element will belong to
Answer the following question.
For the following pair, indicate which of the two species is of large size:
Fe2+ or Fe3+
Answer the following question.
For the following pair, indicate which of the two species is of large size:
Mg2+ or Ca2+
Answer the following question.
Select the smaller ion form the following pair:
K+, Li+
Answer the following question.
Select the smaller ion form the following pair:
N3–, F–
With the help of a diagram answer the questions are given below:
- Which atom should have smaller ionization energy, oxygen, or sulphur?
- The lithium forms +1 ions while beryllium forms +2 ions?
Define ionic radius
Define electronegativity
What are the valence electrons?
Define ionization enthalpy.
How the atomic size vary in a group and across a period? Explain with suitable example.
Give reason.
Alkali metals have low ionization enthalpies.
Give reason.
Noble gases possess relatively large atomic size.
