To verify the previous experiment, the chemistry student carried out the next experiment and recorded the data for you in the following Data Table. Directions: Place 100 mL of filtered, saturated PbCl2 in a 150 mL beaker and put it under a dryer to evaporate the water. Record the necessary data in the Data Table.

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.  

1 is the answer to this problem