Anon-reacting system, comprised of chloroform, dioxane, and ethanol, exists as a 2-phase vapor-liquid mixture at 50cand 55 kpa. it is found, after the addition of some pure ethanol, that the system can be returned to two phase of equilibrium at the initial t and p. in what respect has the system changed, and in what respect has it not changed?

i think a, hope it .

explanation:

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.