The smallest part of an element that can still be identified as that element is a(n)
(a) molecule
(b) proton
(c) electron
(d) atom

atom

Explanation:

(A) molecule is the a group of atoms which are bonded together,

(B) proton it is a particle that comprise an atom

(C) electron it is a particle that comprise an atom

(D) atom is the smallest part of an element that can still be identified

Hence the correct answer is D. The smallest part of an element that can still be identified as that element is an atom.  

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.

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.