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In the following question a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.
Assertion (A): Alkali metals have least value of ionization energy within a period.
Reason (B): They precede alkaline earth metals in periodic table.
- a)Both A and R are true and R is the correct explanation of A.
- b)Both A and R are true but R is not the correct explanation of A.
- c)A is true but R is false.
- d)Both A and R are false.
Correct answer is option 'B'. Can you explain this answer?
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In the following question a statement of Assertion (A) followed by a ...
Both assertion and reason are true but reason is not the correct explanation of assertion. Alkali metals belong to first group and have largest size in a period and hence low I.E.
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In the following question a statement of Assertion (A) followed by a ...
Assertion (A): Alkali metals have the least value of ionization energy within a period.
Reason (R): They precede alkaline earth metals in the periodic table.
Explanation:
- Ionization Energy: Ionization energy is the minimum amount of energy required to remove an electron from an isolated gaseous atom or ion.
- Alkali Metals: Alkali metals are a group of elements that belong to Group 1 of the periodic table, including lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).
- Alkaline Earth Metals: Alkaline earth metals are a group of elements that belong to Group 2 of the periodic table, including beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
Ionization Energy Trend:
- Ionization energy generally increases across a period (from left to right) and decreases down a group (from top to bottom) in the periodic table.
- This trend can be explained by the effective nuclear charge and the distance between the valence electrons and the nucleus.
- Effective nuclear charge is the positive charge experienced by an electron in an atom, which is determined by the number of protons and the shielding effect of inner electrons.
- As we move across a period, the number of protons increases, resulting in a higher effective nuclear charge. This makes it more difficult to remove an electron, leading to an increase in ionization energy.
- Conversely, as we move down a group, the atomic radius increases, and the valence electrons are farther from the nucleus. This reduces the attractive force between the valence electrons and the nucleus, making it easier to remove an electron and decreasing the ionization energy.
Alkali Metals and Alkaline Earth Metals:
- Alkali metals, such as lithium, sodium, and potassium, have the lowest ionization energies within a period.
- This is because alkali metals have a single valence electron in their outermost energy level, which is easily removed due to the low effective nuclear charge and the larger atomic radius.
- Alkaline earth metals, on the other hand, have higher ionization energies compared to alkali metals. This is because alkaline earth metals have two valence electrons, which are held more tightly by the nucleus due to the higher effective nuclear charge.
- Therefore, alkali metals have the least value of ionization energy within a period, and alkali metals precede alkaline earth metals in the periodic table.
Conclusion:
- Both the assertion and reason are true.
- The reason correctly explains why alkali metals have the least value of ionization energy within a period.
- Therefore, the correct option is (a) Both A and R are true and R is the correct explanation of A.
Reason (R): They precede alkaline earth metals in the periodic table.
Explanation:
- Ionization Energy: Ionization energy is the minimum amount of energy required to remove an electron from an isolated gaseous atom or ion.
- Alkali Metals: Alkali metals are a group of elements that belong to Group 1 of the periodic table, including lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).
- Alkaline Earth Metals: Alkaline earth metals are a group of elements that belong to Group 2 of the periodic table, including beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
Ionization Energy Trend:
- Ionization energy generally increases across a period (from left to right) and decreases down a group (from top to bottom) in the periodic table.
- This trend can be explained by the effective nuclear charge and the distance between the valence electrons and the nucleus.
- Effective nuclear charge is the positive charge experienced by an electron in an atom, which is determined by the number of protons and the shielding effect of inner electrons.
- As we move across a period, the number of protons increases, resulting in a higher effective nuclear charge. This makes it more difficult to remove an electron, leading to an increase in ionization energy.
- Conversely, as we move down a group, the atomic radius increases, and the valence electrons are farther from the nucleus. This reduces the attractive force between the valence electrons and the nucleus, making it easier to remove an electron and decreasing the ionization energy.
Alkali Metals and Alkaline Earth Metals:
- Alkali metals, such as lithium, sodium, and potassium, have the lowest ionization energies within a period.
- This is because alkali metals have a single valence electron in their outermost energy level, which is easily removed due to the low effective nuclear charge and the larger atomic radius.
- Alkaline earth metals, on the other hand, have higher ionization energies compared to alkali metals. This is because alkaline earth metals have two valence electrons, which are held more tightly by the nucleus due to the higher effective nuclear charge.
- Therefore, alkali metals have the least value of ionization energy within a period, and alkali metals precede alkaline earth metals in the periodic table.
Conclusion:
- Both the assertion and reason are true.
- The reason correctly explains why alkali metals have the least value of ionization energy within a period.
- Therefore, the correct option is (a) Both A and R are true and R is the correct explanation of A.
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In the following question a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.Assertion (A): Alkali metals have least value of ionization energy within a period.Reason (B): They precede alkaline earth metals in periodic table.a)Both A and R are true and R is the correct explanation of A.b)Both A and R are true but R is not the correct explanation of A.c)A is true but R is false.d)Both A and R are false.Correct answer is option 'B'. Can you explain this answer?
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In the following question a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.Assertion (A): Alkali metals have least value of ionization energy within a period.Reason (B): They precede alkaline earth metals in periodic table.a)Both A and R are true and R is the correct explanation of A.b)Both A and R are true but R is not the correct explanation of A.c)A is true but R is false.d)Both A and R are false.Correct answer is option 'B'. Can you explain this answer? for Class 11 2024 is part of Class 11 preparation. The Question and answers have been prepared according to the Class 11 exam syllabus. Information about In the following question a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.Assertion (A): Alkali metals have least value of ionization energy within a period.Reason (B): They precede alkaline earth metals in periodic table.a)Both A and R are true and R is the correct explanation of A.b)Both A and R are true but R is not the correct explanation of A.c)A is true but R is false.d)Both A and R are false.Correct answer is option 'B'. Can you explain this answer? covers all topics & solutions for Class 11 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for In the following question a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.Assertion (A): Alkali metals have least value of ionization energy within a period.Reason (B): They precede alkaline earth metals in periodic table.a)Both A and R are true and R is the correct explanation of A.b)Both A and R are true but R is not the correct explanation of A.c)A is true but R is false.d)Both A and R are false.Correct answer is option 'B'. Can you explain this answer?.
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