P-1 Periodic Classification of Element Science - P-1 Periodic Classification of Element

……… is used in balloons and in scuba diving.

The halogen which is liquid at room temperature is ………  

Eka-boron was subsequently named as ……..

The law of octaves was given by ……..

Noble gases belong to group …….. in modern periodic table.

First three noble gases.

Two elements having valency 4.

Nonmetals In the third period.

The family of metals having valency one.

The metalloids in the second and third period.

Sodium is more metallic than aluminium.

Fluorine is the most reactive among the halogens.

while going down the second group, the reactivity of the alkaline earth metals increases.

Zero group elements (inert gases) are called noble gases.

what is the difference between the molecules of elements and compounds?

What is the periodic trend in the variation of valency while going down a group? Explain your answer with reference to the group 1, group 2 and group 18.

The table given above is based on modern periodic table. write in it the electronic configuration of the first 20 elements below the symbol and write the valency (as shown in a separate box)

Rearrange the columns 2 and 3 so as to match with the column 1.

Column 1	Column 2	Column 3
i. Triad	a. Lightest and negatively charged particle in all the atoms	1. Mendeleev
ii. Octave	b. Concentrated mass and positive charge	2. Thomson
iii. Atomic number	c. Average of the first and the third atomic mass	3. Newlands
iv. Period	d. Properties of the eighth element similar to the first	4. Rutherford
v. Nucleus	e. Positive charge on the nucleus	5. Dobereiner
vi. Electron	f. Sequential change in molecular formulae	6. Moseley

Distinguish between the following: s-block elements and p-block elements

Distinguish between the following: Groups and periods

write the answers to the questions with reference to the structure of the periodic table.

(a) Which points are considered for the modern periodic table?
(b) How are blocks indicated?
(c) Which elements are present near the zig-zag line?
(d) Draw the electronic configuration of the second-row elements of first group in the periodic table.
(e) In a periodic table while going from left to right atomic radius decreases. Explain. (Practice Activity Sheet – 1)

What are the demerits of Mendeleev’s periodic table?

Discuss the trends in the variation of metallic and nonmetallic properties In a period and in a group.

Depending on electronic configuration the properties of elements vary in different periods. Explain why?

Depending on electronic configuration the properties of the elements vary in different groups. Explain why?

The zig-zag line separates the metals from nonmetals in the periodic table i.e. metals are on the left side and nonmetals are on the right side.

In a group, the metallic character decreases from top to bottom.

In a period, the metallic character increases from left to right.

In a period, atomic sizes increases from left to right.

All the elements of a group have the same number of valence electrons.

The most reactive nonmetal.

The noble gas with the smallest atomic radius.

The most electronegative atom.

The atom having the smallest atomic mass.

The atom having the smallest size.