Final answer:
Al(s) refers to elemental aluminum, which is a neutral element because it has an equal number of protons and electrons. Atoms that differ in the number of neutrons are known as isotopes. A neutral atom is always electrically neutral due to the balanced number of protons and electrons.
Step-by-step explanation:
The concept being discussed here is Al(s), which refers to aluminum in its solid state. To answer the question regarding what Al(s) is, it's essential to understand that aluminum is an element represented by the symbol 'Al' in the periodic table. Atoms of aluminum are neutral in their pure, elemental form. Therefore, the correct answer to the question 'What is Al(s)?' is 'c) Neutral element'.
Atoms that vary in the number of neutrons found in their nuclei are called isotopes. In chemistry, an atom is the smallest unit of an element that retains the properties of that element. Atoms are always neutral in charge because they have the same number of protons as electrons, which balance out their charges.
For example, in the case of carbon-12 (¹²C), the atom contains six protons and six neutrons, and there are six electrons in a neutral ¹²C atom, which results in a net charge of zero. The mass number is 12, indicating its atomic mass. Because the number of protons and electrons are equal, the carbon-12 atom does not carry a net electric charge, making it a neutral atom.