Final answer:
The atom's identity is determined by the number of protons, represented by the atomic number (Z), while its chemical properties are mainly determined by the valence electron configuration. The periodic table organizes elements by increasing atomic number and groups with similar electron configurations, which explains their similar chemical behaviors.
Step-by-step explanation:
The parts of an atom that determine the atom's identity and chemical properties are the number of protons and the electron configuration, particularly the electrons in the outermost shell. The identity of an element is defined by its atomic number (Z), which is the number of protons in an atom's nucleus. The chemical properties of an element, however, are mainly determined by the distribution of electrons, especially those in the outermost shell (valence electrons), as these are the ones that engage in chemical bonding and reactions.
The periodic table is a powerful tool that organizes elements by increasing atomic number and groups elements with similar properties together. Various factors contribute to the arrangement of the periodic table, including the principle that elements with similar electron configurations tend to exhibit similar chemical behaviors. This helps explain the reactivity of elements, as elements that can easily gain or lose electrons from their valence shell tend to be more reactive.
Therefore, any answer stating both the number of protons (which defines the element's identity) and the valence electron configuration would be correct in terms of determining an atom's identity and its chemical properties. Without the specific responses from Students 1 to 4, we cannot determine which student's response is correct. However, the principles stated above are what guide the identification of the correct answer.