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Assertion (A): Mendeleev arranged elemen...

Assertion (A): Mendeleev arranged element in horizontal rows and vertical columns.
Reason (R): Mendeleev ignored the order of atomic weight thinking that the atomic measurements might be incorrect.

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

A is false and R is true.

Text Solution

AI Generated Solution

The correct Answer is:
**Step-by-Step Solution:** 1. **Understanding the Assertion (A):** - The assertion states that "Mendeleev arranged elements in horizontal rows and vertical columns." - This is true; Mendeleev's periodic table was organized into rows (called periods) and columns (called groups or families). 2. **Understanding the Reason (R):** - The reason provided is that "Mendeleev ignored the order of atomic weight thinking that the atomic measurements might be incorrect." - This statement is also true. Mendeleev did recognize that some atomic weights might not be accurate, and he prioritized the chemical properties of elements over their atomic weights when arranging them. 3. **Analyzing the Relationship Between A and R:** - Since both the assertion and the reason are true, we need to determine if the reason correctly explains the assertion. - Mendeleev's decision to arrange elements based on their properties rather than strictly by atomic weight is indeed the reason he organized them into horizontal rows and vertical columns. 4. **Conclusion:** - Both the assertion (A) and the reason (R) are true, and R is the correct explanation of A. Therefore, the correct answer is that both A and R are true, and R is the correct explanation of A. **Final Answer:** Both A and R are true, and R is the correct explanation of A. ---
**Step-by-Step Solution:** 1. **Understanding the Assertion (A):** - The assertion states that "Mendeleev arranged elements in horizontal rows and vertical columns." - This is true; Mendeleev's periodic table was organized into rows (called periods) and columns (called groups or families). 2. **Understanding the Reason (R):** - The reason provided is that "Mendeleev ignored the order of atomic weight thinking that the atomic measurements might be incorrect." ...
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Explore conceptually related problems

Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as : Assertion (A) : Mendeleev's arranged element in horizontal rows and vertical columns. Reason (R) : Mendeleev's ignored the order of atomic weight thinking that the atomic measurements might be incorrect.

Mendeleev arranged elements in order of their increasing atomic number.

Knowledge Check

  • Mendeleev's arranged the then known elements in horizontal rows and vertical columns of a table in the order of their increasong_________in such a way that the elements with similar properties occupied the same vertical column or group.

    A
    atomic density
    B
    atomic volume
    C
    atomic number
    D
    atomic mass

  • Assertion (A): In triad, the three elements have same gaps of atomic masses. ,br> Reason (R): Elements in a triad have similar properties.

    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
    A is false and R is true.

  • Note: Read the assertion and reason carefully and then mark the correct option out of the options given below: Assertion (A) : Moseley showed that atomic number is a more fundamental property than atomic mass. Reason (R) : Atoms of the same element having the same atomic number but different atomic masses are called isotopes.

    A
    Both (A) and (R) are true and (R ) is correct explanation of the assertion.
    B
    Both (A) and (R ) are true but (R ) is explanation of the assertion.
    C
    (A) is true but (R ) is false.
    D
    (A) is false but (R ) is true.

    • Similar Questions

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    Mendeleev arranged elements in the increasing order of their atomic masses. True/False

    State whether the following statements are true or false: (a) Newlands divided the elements into horizontal row of eight element each. (b) According to Mendeleev's periodic law, the properties of elements are a periodic function of their atomic numbers. (c) The elements in a group have consecutive atomic numbers.

    The correct example of pair of elements in Mendeleev's periodic table which not follow increasing order of atomic weight is

    Name the pair of elements in the Mendeleev's periodic table whose positions were not in increasing order of their atomic masses.

    Arrange the above elements vertically downwards in an increasing order of atomic radii.

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