Practice Exercise. A closed steel reaction flask is initially filled with 1.75 mol of nitrogen gas at a pressure of 3.00 atm at 30 °C. After some of the nitrogen gas was allowed to escape, the final pressure

was 1.50 atm at 25 °C. Calculate the mols of nitrogen gas that escaped. ( 0.860 mols )

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.  

the objects have the same charge.