Because they do not have the same qualities therefore they are different
The compound NaH2PO4 name is
sodium dihydrogen phosphate
Explanation
This name is arrived at by using the IUPAC rules of naming compound
1. the metal (sodium)is named first followed by the ligand ( hydrogen and phosphate)
Ligand are molecules that are attached to the metal center.
2. ligand are named using alphabetical order(for our case h for hydrogen come before p for phosphate hence hydrogen is named first)
3. Prefix di is used since hydrogen are two
hence the name of the compound is Sodium dihydrogen phosphate
Full electron configuration of barium: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 6s2
Answer is: the discovery of sub atomic particles like electrons.
J. J. Thomson discovered the electron in 1897.
His "plum pudding" model (1904) suggested: the electrons are embedded in the positive charge.
With this model, he abandoned his earlier hypothesis (the atom was composed of immaterial vortices).
J.J. Thomson placed two oppositely charged electric plates around the cathode ray. He did experiments using different metals as electrode materials and found that the properties of the cathode ray remained constant no matter what cathode material he used.
Tomson concluded that atoms are divisible and that the corpuscles are their building blocks (atoms are made up of smaller particles).
