Describe the contributions of the following scientists to our knowledge of atomic structure: j. j. thomson, r. a. millikan, ernest rutherford, and james chadwick

J.J. Thomson discovered and identified the electron, which was the first subatomic particle to be discovered. R.A. Millikan determined the unit charge of the electron in 1909 with his oil drop experiment. Thus allowing for the calculation of the mass of the electron and the positively charged atoms. Ernest Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus. James Chadwick discovered the Neutron in atoms.

b..

is the correct one

explanation:

covalent bonds form as valence electrons are shared between two atoms. lewis structures and structural formulas are common ways of showing the covalent bonding in organic molecules. formal charge describes the changes in the number of valence electrons as an atom becomes bonded into a molecule.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.