Which of the following best explains why you sanded the copper wire before burning it? to create less friction between the copper and the tongsto make sure that copper metal was exposed on the surface of the wireto make the copper wire flammableto weaken the copper wire so it would be more reactive

Option (b) is the correct answer.

Explanation:

When copper wire is place into the atmosphere or anywhere then there is possibility that some oxide layer or impurity must have deposited over its surface.

So, when we sanded copper wire then these impurities get removed and copper metal gets exposed onto the surface.

Thus, we can conclude that you sanded the copper wire before burning it to make sure that copper metal was exposed on the surface of the wire.

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.