Question

1. The concept of grouping elements into triads was given by ……… .

2. Mendeleev’s basis for the Periodic Table is ……… .

3. The basis for Modern Periodic Table is ……… .

4. (a) Metallic character ……… down the group.
(b) Atomic size ……… along the period.
(c) Electronegative character ……… down the group.

5. Isotopes belong to the same ……… in the Periodic Table.

6. Halogens belong to group ……… of the Periodic Table.

7. An element having electronic configuration (2, 8, 2) belongs to the ……… group.

8. Atoms of different elements with the same number of occupied shells are placed in the same ……… .

9. Valency of elements ……… and then ……… as we move across the period while it remains the same down the group.

10. Non-metals are located on the ……… side of the Periodic Table.

Answer 1

1)dobereiner

2)atomic mass

3)atomic number

4)increase, decrease, decrease

5)block

6)17

7)2nd

8)group

9)increase, decrease

10)right

Answer 2

Answer:

1.Johann Wolfgang Dobereiner,

2.mass number...fundamental property, atomic mass, and chemical properties.

3. atomic number

4.Metallic character increases down each Group

Atomic size decreases along the period.

Electronegative character decreases down the group.

5. same element

6.17

7. 2nd group

8. period

9. On moving across a period the number of electrons increases but as the valence electrons crosses 4 it is easier for elements to accept electrons. So the valency decreases.

10. right side of the periodic table,

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