Question

1.
(i) State Modern Periodic Law.
(ii) What is the cause of periodicity in properties of
elements.​

Answer 1

Answer:

(1) Modern periodic table is the periodic function of the properties of all elements.

(2)The causes of all elements in period particular based are as follows :-

* In properties of elements in period is the atomic shell or energy level remains.

* In period, if you take one element from them; the closest element having more similar properties then that of differ elements.

*Going form left to right in period the electric-negativity increase.

Explanation:

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Answer 2

Explanation:

2)The cause of periodicity in properties is the repetition of similar outer electronic configuration after certain regular intervals.

For example, all the elements of group LA i.e., alkali metals, have similar outer electronic configuration as ns1.

Where n refer to the number of outermost principal shell.

In a similar manner all the halogens i.e., elements of group VILA have similar other electronic configuration i.e., ns2 ns5 and hence possess similar properties.