What is the concentration, in millimolar, of a 1 mg/ml solution of nacl (molecular weight = 58 da)?

Explanation:

Relation between molarity and molar mass is as follows.

             Molarity =

It is given that mass is 1 mg/ml which is also equal to g.

Molecular mass = 58 Da = 58 g/mol

Volume = 1 ml

Therefore, calculate molarity as follows.

         Molarity =

                       =  

                       = 0.0172 molar

It is known that 1 molar equals 1000 millimolar.

So,               0.0172 molar =

                                          = 17.2 millimolar

Thus, we can conclude that the concentration of given solution is 17.2 millimolar.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.