Correct Answer - Option 2 : Only II
The correct answer is Option(2) .i.e.Only II.
- At increasing order of atomic weights, the elements were arranged in horizontal rows called 'periods' and vertical columns called ''groups'.
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Elements in a similar group had the same 'valency' and the same chemical properties.
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Mendeleev’s Periodic Table:
- Mendeleev introduced a table that consists of elements, called Mendeleev’s periodic table.
- In the increasing order of their atomic masses, he arranged the elements accordingly.
- This arrangement posses Mendeleev to place elements in horizontal rows known as periods & vertical columns known as groups.
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Periodic Law of Mendeleev:
- The chemical & physical properties of elements are periodic functions according to their atomic weights.
- The following table of Mendeleev shows the list of elements with respective atomic masses.
Series |
Group I |
Group II |
Group III |
Group IV |
Group V |
Group VI |
Group VII |
Group VIII |
1 |
H=1 |
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2 |
Li = 7 |
Be = 9.4 |
B = 11 |
C = 12 |
N = 14 |
O=16 |
F = 19 |
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3 |
Na=23 |
Mg=24 |
Al=27.3 |
Si=28 |
P=31 |
S=32 |
Cl = 35.5 |
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