3. Satellite technology is best used to a) view the underwater world.
b) view the ocean's surface and large areas at a distance.
c) access areas of the deep sea where people cannot go.
d) give people a remote area to do their research closer to their subject.

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.