2-An atom would be define as the smallest unit of matter and it can´t be created or destroyed.
3-Democritus saidthat matter is composed of empty spaces were atoms move and Dalton said that matter was made from small particles called atoms.
TheDemocritus´method hampers the acceptance of his ideas because he didn´t have evidence to prove his theory.
5.-Democritus and Dalton both believed in theexistence of atoms but one proposes that matter is composed by atoms and the other one doesn´t.
Assessments 4.3 page 104
18-the isotopes,is the subatomic particle that identifies an atoms as that of a particular element, because they are atoms of the same elements with the samenumber of protons but different number of neutrons.
19-isotopes are atoms of the same element with the same number of protons but differentnumber of neutrons ex. Carbon
20.The existence of isotopes highlight the difference of neutrons that´s why it is not a whole number21.-Nitrogen has two naturally occurring isotopes, N-14 and N-15. The atomic mass of nitrogen is 14.007 amu. Which isotope is more abundant in nature?N-15 because is closer to the one in the periodic table
22.- The steps in the process for calculating average atomic mass about the givendata of the isotopes of an element are; multiply the mass of each isotope by its percent abundance; then, sum the mass of all the isotopes