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

According to Mendeleev's periodic law.properties of elements are periodic function of their ____________.

In _____________ block of the modern periodic table non-metals are found.

Lithium (Li), _____________ and potassium (K) is Dobereiner's triad.

Alkaline earth metals have valency 2. This means that their position in the modern periodic table is in ____________

In Dobereiner's triads Li, Na, K, the atomic masses of lithium and potassium are 6.9 and 39.1 respectively, then what will be the atomic mass of sodium?

Atomic radius goes an increasing down a group.

Elements belonging to the same group have the same valency.

While going from left to right within a period, the size of atom decreases

State Dobereiner's law of triad. Give one example of it.

Define periods and groups of modern periodic table.

Metallic character goes on decreasing whill going from left to right in a period.

Write the modern periodic law and also give the names of 'blocks' in modern periodie table.

An element has its electronic configuration as (2,8,2). Answer the following:
i. What is the atomic number of this element?
ii. What is the group of this element?
iii. To which period does this element belong?

Select the appropriate option and complete the following paragraph:
(Metals, non-metals, metalloids, four, seven, s-block, p-block, d-block, f-block.)
On the basis of electronic configuration, elements in the modern periodic table are classified into ___________ blocks. Group 1 and 2 elements are included in __________ and all these elements are metais. (except hydrogen). Group 13 to 18 elements are included in _________ This block contains metals, non-metals and metalloids Group 3 to 12 elements are included. in __________ and all the elements are ___________. Elements shown at the bottom of the periodic table i.e., Janthanides and actinides constitute _________ and all these elements are metals.

Write the name of the atom having the smallest size.

Write the demerits of Mendeleev's periodic table.

Taking into consideration the period of the elements given below, answer the following questions:

Element	Atomic radius (pm)
O	66
B	88
C	77
N	74
Be	111
Li	152

i. Arrange the above elements in a decreasing order of their atomic radii.
ii. State the period to which the above elements belong.
iii. Why this arrangement of elements is similar to the above period of the modern periodic table?
iv. Which of the above elements have the biggest and the smallest atom?
v. What is the periodic trend observed in the variation of atomic radius while going from left to right within a period?

Observe the following diagram and write the answers of the following questions:

i. Write the atomic numbers of first two elements in the second group.
ii. Write the number of valence electrons of the elements in the halogen group.
iii. Draw the diagram of electronic configuration of magnesium atom.
iv. After completion of a period, what change does take place in the electronic configuration of the next element?
v. Write the names of any two elements from the diagram which do not take part in chemical reaction.

Zinc, iron, phosphorus, sodium