Answer:
The physical and chemical properties of elements are periodic function of their atomic weights. This is Mendeleev's periodic law.
63 elements were classified by Mendeleev.
plz mark brainliest✌️✌️
Answer: The balanced equation for the given reaction is
.
Explanation:
A chemical equation which contains same number of atoms on both reactant and product side.
For example, 
Here, number of atoms on reactant side are as follows.
Number of atoms on product side are as follows.
To balance this equation, multiply
by 2 on reactant side and multiply
by 2. Hence, the equation will be re-written as follows.

Here, number of atoms on reactant side are as follows.
Number of atoms on product side are as follows.
Now, there are same number of atoms on both reactant and product side. So, this equation is balanced.
Thus, we can conclude that the balanced equation for the given reaction is
.
Nobles gases, since they all have 8 e- on their last layer of electrons.
This doesn’t have a multiple choice part to answer.