An element containing a charge.

The Charge of Elements

For example, sodium is an element with 11 protons within the nucleus and 11 electrons. Another example of an element is carbon, which has six protons within the nucleus and six electrons. In both cases, these elements have a neutral charge.

Explanation: That means an atom with a neutral charge is one where the number of electrons is equal to the atomic number. Ions are atoms with extra electrons or missing electrons. When you are missing an electron or two, you have a positive charge. When you have an extra electron or two, you have a negative charge.

what is the volume occupied by 40 grams of argon gas (ar) at standard conditions? what volume, in liters, is occupied by 1.5 x 1023 

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.