Hg is an atom , because an atom means that a smallest individual spece and it cannot be undivisible further. H+ is an ion, it is a spece was formed by the H atom after lost one electron from it. H2O is a molecule ,and it has obtained by the reaction of H2 atoms and O atoms. O2 and N2 , Ar and CO2 both are called as mixures becaues those were formed by the mixing from two individual species or molecules. NaCl is a compound , it has the fixed proportion of both Na and Cl in its compound. Solution Hg is an atom , because an atom means that a smallest individual spece and it cannot be undivisible further. H+ is an ion, it is a spece was formed by the H atom after lost one electron from it. H2O is a molecule ,and it has obtained by the reaction of H2 atoms and O atoms. O2 and N2 , Ar and CO2 both are called as mixures becaues those were formed by the mixing from two individual species or molecules. NaCl is a compound , it has the fixed proportion of both Na and Cl in its compound..

1. Hg is an atom , because an atom means that a smallest individual spece
and it cannot be undivisible further.
H+ is an ion, it is a spece was formed by the H atom after lost one electron from it.
H2O is a molecule ,and it has obtained by the reaction of H2 atoms and O atoms.
O2 and N2 , Ar and CO2 both are called as mixures becaues those were formed
by the mixing from two individual species or molecules.
NaCl is a compound , it has the fixed proportion of both Na and Cl in its compound.
Solution
Hg is an atom , because an atom means that a smallest individual spece
and it cannot be undivisible further.
H+ is an ion, it is a spece was formed by the H atom after lost one electron from it.
H2O is a molecule ,and it has obtained by the reaction of H2 atoms and O atoms.
O2 and N2 , Ar and CO2 both are called as mixures becaues those were formed
by the mixing from two individual species or molecules.
NaCl is a compound , it has the fixed proportion of both Na and Cl in its compound.