Modern atomic theory defines matter as discrete units composed of a dense central nucleus containing positively charged protons and neutral neutrons, surrounded by negatively charged electrons in quantized orbits known as shells or energy levels. An atom's chemical identity is determined by its fixed atomic number (number of protons), while electrical neutrality arises from the equality between proton count and electron count within an orbital system governed by specific capacity limits for each shell. The fundamental mechanism driving chemical reactions involves atoms achieving stable electronic configurations, typically through the transfer or sharing of valence electrons to achieve a full outer octet state.
Modern atomic theory defines matter as discrete units composed of a dense central nucleus containing positively charged protons and neutral neutrons, surrounded by negatively charged electrons in qua…