The postulates of Dalton's theory were:
1) Elements are made of extremely small particles called atoms
2) <span>Atoms of a given element are identical in size, mass, and other properties
</span>3) <span>Atoms cannot be subdivided, created, or destroyed</span>
4) Atoms combine in whole number ratio to form compounds
5) Chemical reactions are the rearrangement of atoms
The third postulate has been disproved by modern science, in which the atom has been split and been subdivided into smaller parts such as the neutron, proton and electron, which are further subdivided into quarks, gluons, and kaons.
The second postulate was also disproved upon the discovery of isotopes.
Isotopes
Mass atom of Neon: 20.1797 amu
Mass atom X = mass isotope 1 . % + mass isotope 2.% +.....

A binary ionic compound is composed of ions of two different elements. One of which is a metal, and the other a non-metal
The knowledge of periodic table would be important in these three different careers such as medicine, pharmacology and engineering.
<h3>What is the importance of periodic table in following careers?</h3>
Periodic table is organised the whole elements vertically in groups and horizontally in periods with increasing atomic number.
The knowledge of arrangement of these elements serves alot of purposes in the following three different careers:
- Medicine: The element, iron is an important metal in the periodic table used in treatment of low blood levels.
- Pharmacology: The transition metals are useful in the field of pharmacology for the production of drugs. Example of such elements are chromium, manganese, cobalt, nickel, copper, and molybdenum.
- Engineering: The information of elements in the periodic table helps engineers in designing of materials used for constructions.
Therefore, the knowledge of periodic table is very important in these three different careers such as medicine, pharmacology and engineering.
Learn more about period table here:
brainly.com/question/15987580