What are 'periods'. State the correlation of a period number with the elements of that period.

State the reason for periodicity of elements in periods and groups.

State the important salient features of the modern periodic table. State how separation of elements and periodicity of elements forms an important feature of the modern periodic table.

The number of element present in the fifth period is

Number of elements present in longest period

The period number in the long form of the periodic table is equal to (A)Magnetic quantum number of any element of the period (B)Atomic number of any element of the period (C)Maximum principal quantum number of any element of the period (D)Maximum azimuthal quantum number of any element of the period

Name or state the following with reference to the elements of the first three periods of the periodic table. Metalloid in Period 3.

Name or state the following with reference to the elements of the first three periods of the periodic table. Alkaline earth metal in Period 3.

Assertion:In the present form of periodic table,the period number corresponds to the highest principal quantum number of the elements in the period. Reason:Elements having similar outer electronic configuration in their atoms belongs to same period.

Number of elements present in the shortest period.

Assuming that elements are formed to complete the seventh period, what would be the atomic number of the alkaline earth metal of the eighth period?