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Assertion: Boron has a smaller first ion...

Assertion: Boron has a smaller first ionisation enthalpy than beryllium.
Reason: The penetration of a `2s` electron to the nucleus is more than the `2p` electron, hence `2p` electorn is more shielded by the inner core of electrons than the 2s electrons.

A

Assertion is correct statement and reason is wrong statement.

B

Assertion and reason both are correct statements and reason is correct explanation of Assertion.

C

Assertion and reason both are wrong statements.

D

Assertion and wrong statements and reason is correct statements.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the assertion-reason question regarding the ionization enthalpy of boron and beryllium, we will follow these steps: ### Step 1: Understand the Assertion The assertion states that boron has a smaller first ionization enthalpy than beryllium. ### Step 2: Know the General Trend In general, as we move from left to right across a period in the periodic table, the ionization enthalpy tends to increase. This is due to the increasing nuclear charge which holds the electrons more tightly. ### Step 3: Compare the Elements Beryllium (Be) is in Group 2 and has the electronic configuration of 1s² 2s². Boron (B) is in Group 13 with the electronic configuration of 1s² 2s² 2p¹. ### Step 4: Analyze the Electronic Configurations - Beryllium has a completely filled 2s subshell (2s²). - Boron has one electron in the 2p subshell (2p¹), which is not completely filled. ### Step 5: Consider Penetration and Shielding The 2s electrons have a greater penetration towards the nucleus compared to 2p electrons. This means that the 2s electrons experience a stronger attraction to the nucleus than the 2p electrons. ### Step 6: Conclusion on Ionization Enthalpy Since beryllium has a completely filled 2s subshell, it is more stable and requires more energy to remove an electron compared to boron, which has a less stable configuration due to the presence of a single 2p electron. Therefore, beryllium has a higher ionization enthalpy than boron. ### Step 7: Evaluate the Reason The reason states that the penetration of a 2s electron to the nucleus is more than that of a 2p electron, and hence the 2p electron is more shielded by the inner core of electrons than the 2s electrons. This statement is correct and explains why beryllium has a higher ionization enthalpy than boron. ### Final Conclusion Both the assertion and the reason are correct, and the reason correctly explains the assertion. Therefore, the answer is that both the assertion and reason are correct, and the reason is the correct explanation of the assertion. ---
To solve the assertion-reason question regarding the ionization enthalpy of boron and beryllium, we will follow these steps: ### Step 1: Understand the Assertion The assertion states that boron has a smaller first ionization enthalpy than beryllium. ### Step 2: Know the General Trend In general, as we move from left to right across a period in the periodic table, the ionization enthalpy tends to increase. This is due to the increasing nuclear charge which holds the electrons more tightly. ...
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