Final answer:
The incorrect statement is identified among the options given, specifically regarding ionization enthalpy in relation to screening effect.
Explanation:
The incorrect statement among the options provided is:
- More the screening effect, lesser will be the ionisation enthalpy: This statement is incorrect as higher screening effect leads to lower ionization enthalpy.
- Size of a cation is smaller than its parent atom
- 5th period of the periodic table consists of 32 elements
- Electron affinity increases along the period
Ionization energy increases across a period due to the increased effective nuclear charge, attracting electrons more strongly.
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