There are 30 inches in 2.5 just know that a foot is 12 inches so 12 times 2.5 is 30
This is called a life span.
When Newlands tried to create a periodic table, his tried to conform to the "Rule of Octaves" he had discovered. He had the right idea, in that if you arrange the elements by atomic weight there would be similarities every 7 elements (not 8 because noble gases hadn't been discovered yet) but he tried to push this rule so much that he would put multiple elements in the same box to try to keep the rule. Mendeleev, however, left gaps in this table for undiscovered elements, which paved the way for our modern periodic table.
Density as you say Saturn as you say Jupiter as you say big stuff chemistry mike h20 is water
