In the periodic table, there are seven horizontal rows of elements called periods.
Answer:
Getting coated with tarnish
Explanation:
Silver, the original substance is combining with a new substance tarnish to make a whole new chemical.
The noble gases, because they already have a full valence shell
Aqua regia is used to bring precious metals into the solution .

This is the balanced reaction of Pt (platinum) .
<h3>What is aqua regia ?</h3>
It is a mixture of concentrated nitric acid and hydrochloric acid .there is three part of concentrated HCl and 1 part of concentrated nitric acid .
it is red or yellowish liquid . it is extremely corrosive and can cause skin burns . it is frequently used to dissolve gold and platinum .
The equation of reaction of aqua regia with gold :

Learn more about aqua regia here :
brainly.com/question/12982022
#SPJ4
Answer: 1.91cm3
Explanation:
10.49g of silver dissolves is 1cm3 of solution.
Therefore 20g of silver will dissolve in = 20/10.49 = 1.91cm3 of the solution.