The following are scientific observations which led to development and changes of periodic table: Dmitri Mendeleev is the first periodic table organized 63 known element according to its properties, organized into rows and columns and inscribed name, mass and chemical properties on each element. Julius Lothar Meyer who independently worked in Germany with Ernest Rutherford. They experimented with 38 metals and found out that the positive charge of each element nucleus increased by one from element to element and organized the periodic table that tip to modern explanation of atomic number and the recognition of atomic number was the basis for organization of periodic table.
Answer:
<u><em>Pentane </em></u>
Explanation:
since we have in here CH3-CH2-CH2-CH2-CH3 5 Carbon atoms and 12 Hydrogen making it 
Covalent bonding!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I hope this picture helps
