What does the negative electronic energy (negative sign for all values of energy) for hydrogen atom means? (a) The energy of an electron in the atom is lower than the energy of a free electron at rest which is taken as zero. (b) When the electron is free from the influence of nucleus it has a negative value which becomes more negative. (c) When the electron is attracted by the nucleus the energy is absorbed which means a negative value. (d) Energy is released by hydrogen atom in ground state.

Understanding the electron energy levels within an atom is crucial for grasping various phenomena in physics and chemistry. These energy levels, also known as electron shells, are defined areas where electrons are most likely to be found. In the context of the hydrogen atom, which has one electron, this electron can occupy different energy levels, each characterized by a specific energy value.

The energy levels are quantized, meaning the electron can possess only specific discrete energy values and nothing in between. The negative sign in the energy value represents a system that has less energy than a free electron at rest — with free electron's energy considered as the zero or reference point. In essence, when an electron is bound within an atom, it has lower energy than when it is free and unassociated with any nucleus. This concept helps us understand that it requires energy to remove an electron from an atom because the electron is in a lower energy, more stable state when it is bound.

These energy levels are crucial for understanding how atoms absorb and emit light, as the transition of an electron between levels results in the absorption or emission of a photon with energy corresponding to the difference between these levels.

The hydrogen atom serves as the simplest and most fundamental atomic model, composed of a single proton as its nucleus and one electron. Despite its simplicity, the hydrogen atom plays a significant role in quantum mechanics and the development of atomic theory.

In the hydrogen atom, the energy levels of the electron are represented by the principal quantum number, denoted by the symbol 'n'. Each energy level with a different 'n' value has a distinct energy associated with it. When discussing negative electronic energy, it refers to the energy state of the electron when it is in one of the allowed orbits around the nucleus. As per the Bohr model of the hydrogen atom, when the electron is in its lowest energy state, also known as the ground state, it's at the first energy level (n=1) and has the most negative energy value.

The negative value indicates that work must be done to remove the electron from the atom, which corresponds to reaching the point of zero energy where the electron becomes free. This is essential in understanding phenomena such as ionization energy and the emission spectra of the hydrogen atom.

The atomic structure encompasses the arrangement of electrons around the nucleus of an atom. The nucleus contains protons and neutrons, which account for the majority of an atom's mass, while the electrons orbit the nucleus in various energy levels. A crucial aspect of this structure is that it defines the chemical properties of an element and the manner in which it interacts with other atoms.

An atom's electronic configuration, which denotes the distribution of electrons across the different energy levels, is pivotal in understanding the atom's reactivity and stability. Atoms with a full outer electron shell are generally more stable and less reactive. An atom is most stable when its electrons are in the lowest possible energy levels — a state also reflected by the negative electronic energy. Reaching a lower energy state is naturally favored because it reflects increased stability.

In conclusion, an atom's electronic structure is vital in explaining not only the chemical behavior of elements but also the fundamental nature of matter and energy interactions. The concept of negative electronic energy plays an integral role in this understanding, indicating the binding energy that holds electrons near the nucleus, and how altering this energy can result in different physical and chemical properties.