Mendeleev’s principle of chemical periodicity states that when the elements are arranged according to their atomic numbers. this periodic law allows elements with similar properties to appear at regular intervals. predict the group of elements and their number of valence electrons that will combine in a 2: 1 ratio to with sodium.
a. bromine, chlorine, iodine, 7
b. sulfur, selenium, polonium, 6 eliminate
c. hydrogen, fluorine, potassium, 1
d. calcium, phosphorus, tellurium, 2

Acompound contains c, h, and o atoms. when 1.130 g of the compound is burned in oxygen, 1.064 g co2 and 0.3631 g h2o are produced. what is the empirical formula of this compound?

16. why must the number of electrons lost equal the number of electrons gained in every redox reaction? use 3 – 4 sentences in your own words to address this question. 18. what type of radiation is emitted when chromium-51 decays into manganese-51? show the nuclear equation that leads you to this answer. 19. a radioactive nucleus alpha decays to yield a sodium-24 nucleus in 14.8 hours. what was the identity of the original nucleus? show the nuclear equation that leads you to this answer.

Upon decomposition, one sample of magnesium fluoride produced 1.65 kg of magnesium and 2.56 kg of fluorine. a second sample produced 1.32 kg of magnesium. part a how much fluorine (in grams) did the second sample produce?