Neutrons don’t carry an electrical charge, meaning that adding or subtracting them from the nucleus will not change the electrical charge of the nucleus of an atom. But, adding/removing neutrons changes the mass of the nucleus. This is how isotopes are formed.
The answer is 3). This is because elements are the simplest form of a substance, and cannot be broken down any further. Compounds on the other hand are much more complex than elements and can be broken down INTO elements.
For example, Na, sodium, is an element and cannot be broken down further. H2O, water, is a compound and can be broken down into Hydrogen and Oxygen.
A standard drink of beer is 12 ounces