Atoms, Molecules, and Ions Dalton’s Atomic Theory: Elements are composed of extremely small particles called atoms. All atoms of a given element are identical, having the same size, mass, and chemical properties. The atoms of one element are different from the atoms of all other elements. Compounds are composed of atoms of more than one element. In any compound, the ratio
of the numbers of atoms of any two of the elements present is consistently either an integer or a simple function.
A chemical reaction involves only the separation, combination, or rearrangement of atoms; it does not result in their creation or destruction. Law of conservation of mass: Mass can neither be created nor destroyed… just transferred from one form to another. Law of definite proportions: All samples of a compound have the same ratio of their elements. (If the ratio charges, the compounds change!!!). Law of multiple proportions: If elements form multiple compounds, ratio of second element to first in the two is proportional.
Rutherford’s model of the atom: Atomic radius ~100pm= 1x10-10m Nuclear radius ~5x 10-3pm= 5 x 10-15m Atomic number and mass number:
of the numbers of atoms of any two of the elements present is consistently either an integer or a simple function.
A chemical reaction involves only the separation, combination, or rearrangement of atoms; it does not result in their creation or destruction. Law of conservation of mass: Mass can neither be created nor destroyed… just transferred from one form to another. Law of definite proportions: All samples of a compound have the same ratio of their elements. (If the ratio charges, the compounds change!!!). Law of multiple proportions: If elements form multiple compounds, ratio of second element to first in the two is proportional.
Rutherford’s model of the atom: Atomic radius ~100pm= 1x10-10m Nuclear radius ~5x 10-3pm= 5 x 10-15m Atomic number and mass number:
