(a) In the modem periodic table, which are the metals among the first ten elements?(b) What is the significance of atomic number in the modern classification of elements? Explain with the help of an example.


(a) In the modern periodic table, Lithium(Li) and beryllium(Be) are metals among the first ten elements.

(b) The significance of atomic numbers in the periodic table is that it relates to the periodicity in the properties of elements to the periodicity in their electronic configurations. The elements placed in the same group show similar chemical properties.

For example, the atomic number of lithium is 3 (2,1). It is placed in the first group as the valence electron is 1 and sodium has the atomic number of 11 (2,8,1) having 1 valence electron and belongs to the same group.

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Updated on: 10-Oct-2022

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