why is the atomic number the number of protons
Atomic number The sum of the atomic number Z and the number of neutrons, N, gives the mass number A of an atom. Since protons and neutrons have approximately the same mass (and the mass of the electrons is negligible for many purposes) and the mass defect of nucleon binding is always small compared to the nucleon mass, the atomic mass of any atom, when expressed in unified atomic mass units (making a quantity called the "relative isotopic mass"), is within 1% of the whole number A.
Rate equation k is the first order rate constant, which has units of 1/s or sâˆ’1.
Isotope Isotopes are atoms of the same element having the same numbers of protons (atomic number), but different numbers of neutrons. They have same chemical properties due to the same electron configuration, but different physical properties.[citation needed]
Boyle's law where P is the pressure of the gas, V is the volume of the gas, and k is a constant.
Hundreds and thousands Hundreds and thousands used incorrectly instead of hundreds of thousands to mean "an indefinite but emphatically large number".
Atomic radius Depending on the definition, the term may apply only to isolated atoms, or also to atoms in condensed matter, covalently bound in molecules, or in ionized and excited states; and its value may be obtained through experimental measurements, or computed from theoretical models. The value of the radius may depend on the atom's state and context.[1]