Explain about the structural features of Moseley's long form of periodic table.

Explanation

(i) The long form of periodic table of the elements is constructed on the basis of modern periodic law. The arrangement resulted in repeating electronic configurations of atoms at regular intervals.
(ii) The elements placed in horizontal rows are called periods and in vertical columns are called groups.
(iii) According to IUPAC, the groups are numbered from 1 to 18.
(iv) There are 18 vertical columns which constitute 18 groups or families. All the members of a particular group have similar outer shell electronic configuration.
(v) There are 7 horizontal rows called periods.

The elements are shown in the above table along with its atomic number.
(vi) The atomic number also indicates the number of electrons in the atoms of an element.
(vii) This periodic table is important and useful because we can predict the properties of any element using periodic trend, even though that element may be unfamiliar to us.