121. Задачка по химии №012 172

69. What is the modern formulation of the periodic law? Explain why in the periodic table of elements argon, cobalt, tellurium and thorium are placed before potassium, nickel, iodine and protactinium, respectively, although they have a large atomic mass.

If you do not open the file - install the RAR archiver. Inside the archive you will find a solution in Word format.