Joseph proust showed that when elements combine to form new substances, they do so in specific mass ratios. a) trueb) false

option A) True

Explanation:

Joseph Proust is the founder of the Law of Definite proportion. This law states that two elements will always combine together to form a chemical compound and this will be in the same proportion by mass.

For Example: 2 moles of Hydrogen (H2) ALWAYS combine with 1 atom of Oxygen (O) to yield water (H2O)

So, the answer is True

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.