Final answer:
To distinguish stable from unstable atoms, examine their electron configuration and mass number, where a stable configuration and a suitable neutron-to-proton ratio indicate stability. The atomic number helps identify the element, and a binding energy per nucleon graph can assess nuclear stability.
Step-by-step explanation:
To tell the difference between a stable and unstable atom, one should primarily examine the electron configuration and mass number.
Stable atoms typically have complete electron shells or a stable configuration of protons and neutrons in their nuclei.
An unstable atom usually has an excess of energy in the nucleus, leading to various forms of radioactive decay.
The atomic number, which indicates the number of protons in an atom, does not directly tell us about the stability of the atom, though it does help identify the element.
The color of an atom is not relevant to its stability. Examining the mass number is especially important in recognizing isotope stability, as isotopes with a high or low neutron-to-proton ratio may be unstable.
To clarify concepts mentioned, mass number is the sum of protons and neutrons in the nucleus, whereas atomic number is the number of protons, which defines the element. Isotopes are variants of an element with different neutron numbers.
Using the binding energy per nucleon (BEN) graph, one can assess stability; nuclei with more binding energy per nucleon are typically more stable.