: Modern theory posits that matter is composed of these discrete units, as established by pioneers like John Dalton , who proposed that atoms combine in fixed ratios to form compounds. Scientific Reporting and Application
: Students use reports to communicate findings on atomic structure , focusing on observations from simulations or experiments like flame tests and spectrometry.
: Protons and neutrons together make up the mass number ( Atomic Keys
: Neutral particles (no charge) also found in the nucleus.
: The number of protons is the atomic number ( : Modern theory posits that matter is composed
: Electrons are significantly smaller than nucleons and are primarily responsible for chemical bonding and reactivity . Key Metrics and Concepts
: A standard unit used to express the mass of atoms; protons and neutrons each have a mass of approximately , while electrons are roughly : The number of protons is the atomic
). Atoms of the same element with different numbers of neutrons are called . Electrons : Negatively charged ( -1negative 1