Which of dalton's postulates about atoms are inconsistent with later observations? do these inconsistencies mean that dalton was wrong? is dalton's model still useful? explain?

1)  Dalton stated that atom is matter that can not be divided, but it is proved that the atom can be divided into subatomic particles  (electrons, protons and neutrons).

2) He stated that atoms of one element can not be changed into atoms of other  elements, but now that is possible by nuclear reactions.

Today we still use his postulate: Atoms combine in the ratio of small whole numbers to form stable compounds, for example H₂O.

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o