How did Mendeleev come up with the first periodic table of the elements? (1 point) A He determined the mass of atoms of each element.
B He estimated the number of electrons in atoms of each element.
C He arranged the elements by different properties to find a pattern.
D He organized the elements by their atomic number.​

Iknow #2 is d. i just need to know why

You are attempting to recrystallize a crude product mixture. you add the appropriate amount of hot solvent and are allowing the solution to slowly cool to room temperature. however, at room temperature no crystals have appeared, which of the following methods should be used to induce crystallization? choose all correct answers. a) place the flask in an ice bath. b) swirl the contents of the flask. c) add a small seed crystal of the desired product. d) scratch the inside of the glassware using a stir rod. it can be multiple choices

The molar mass of iron(fe) is 55.8 g/mol. what is the mass in grams of 2.25 moles of iron?