Question

(b) for a stable, neutral atom, how many protons, neutrons, and electrons can the carbon have? (c) when does the carbon atom become an ion? (d) when does the carbon atom become unstable?

Explanation:

(b)

Step1: Recall carbon's atomic number

Carbon has an atomic number of 6. In a neutral atom, protons = electrons = atomic number. So protons = 6, electrons = 6.

Step2: Recall carbon's mass number (most common isotope)

The most common carbon isotope is carbon - 12, where mass number \( A=12 \). Mass number \( A=\text{protons}+\text{neutrons} \). So neutrons \( = A - \text{protons}=12 - 6 = 6 \). For other stable isotopes like carbon - 13, neutrons \( = 13 - 6=7 \), but carbon - 12 is the most stable and common.

A carbon atom becomes an ion when it gains or loses electrons. Carbon has 4 valence electrons. It can gain electrons (to form an anion, e.g., in compounds like carbides where it gains electrons) or lose electrons (to form a cation, though less common as it requires energy to lose 4 electrons, but can happen in some high - energy or specific chemical environments) to achieve a stable electron configuration (like a noble gas configuration, e.g., gaining 4 electrons to have 8 valence electrons like neon, or losing 4 to have 0 valence electrons like helium).

A carbon atom becomes unstable when its nucleus has an unstable ratio of protons to neutrons (for radioactive isotopes, e.g., carbon - 14 has 6 protons and 8 neutrons, which is an unstable ratio, leading to beta decay) or when the electron configuration is disrupted in a way that makes it highly reactive (though chemical instability due to electrons is different from nuclear instability; nuclear instability is due to proton - neutron imbalance in the nucleus, and chemical instability is due to having unpaired electrons or an incomplete octet, but the question likely refers to nuclear instability here as "unstable" for atoms often relates to radioactivity). Radioactive carbon isotopes (like \( ^{14}\text{C} \)) have an unstable nucleus because the number of neutrons (8 in \( ^{14}\text{C} \)) relative to protons (6) is such that the strong nuclear force can't hold the nucleus together against the electrostatic repulsion of protons, leading to decay. Also, in some extreme chemical environments where the atom can't achieve a stable electron configuration (though this is more about reactivity than the atom being "unstable" in the nuclear sense), but nuclear instability is the main case for carbon atom instability.

Answer:

For a stable, neutral carbon atom (most commonly carbon - 12): Protons = 6, Neutrons (in \( ^{12}\text{C} \)) = 6, Electrons = 6. For \( ^{13}\text{C} \) (also stable), Neutrons = 7, protons and electrons still 6.

(c)