The order of elements in the periodic table is based on
a. the number of protons in the nucleus.
b. the electric charge of the nucleus.
c. the number of neutrons in the nucleus.
d. atomic mass.
select the best answer from the choices provided
a
b
c
d

What does x represent in the formula for the compound xcl4?

Can someone me with 1 to 4 plz. fast

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н, о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.