3. Roger ran 50 meters to the left, turned around and ran 100 meters to the right, and then turned around once more and ran 10 meters to the left. Determine his total displacement and distance traveled from the starting point.

Distance=160 meters, Displacement = 40 meters right

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.