Structure of the Atom - A Deeper Look into Atomic Structure

Subatomic Particles: Atoms consist of protons ($p^+$), neutrons ($n^0$), and electrons ($e^-$). Protons and neutrons reside in the nucleus, while electrons revolve around it.

Thomson's Model: Proposed that an atom consists of a positively charged sphere with electrons embedded in it, like seeds in a watermelon.

Rutherford's $\alpha$-particle Scattering: Showed that most of the atom is empty space and that there is a small, dense, positively charged nucleus at the center. The radius of the nucleus is about $10^5$ times smaller than the radius of the atom.

Bohr's Model: Electrons revolve in discrete orbits called shells ($K, L, M, N$). While revolving in these orbits, electrons do not radiate energy.

Electronic Configuration: The distribution of electrons is governed by the Bohr-Bury scheme. The maximum number of electrons in a shell is given by $2n^2$, where $n$ is the orbit number.

Valency: The combining capacity of an atom, determined by the number of electrons in its outermost (valence) shell. Atoms react to achieve a stable octet ($8$ electrons in the valence shell).

Atomic Number ($Z$): The total number of protons in the nucleus of an atom.

Mass Number ($A$): The sum of the total number of protons and neutrons in the nucleus of an atom.

Isotopes: Atoms of the same element having the same atomic number but different mass numbers (e.g., $^{1}_{1}H$, $^{2}_{1}H$, $^{3}_{1}H$).

Isobars: Atoms of different elements with the same mass number but different atomic numbers (e.g., $^{40}_{18}Ar$ and $^{40}_{20}Ca$).