I need help please. ​

Which is true of chemicals? a. things containing chemicals always cost a lot of money. b. chemicals are never dangerous. c. chemicals are in many substances in a home. d. chemicals are rarely found on earth.

Which is true of transition metals when moving from left to right on the periodic table? the d sublevels are not filled across the period. the cation radii become larger across the period. atomic radii increase slightly and then start to decrease. atomic radii decrease slightly and then start to increase. o

Rank the four gases (air, exhaled air, gas produced from from decomposition of h2o2, gas from decomposition of nahco3) in order of increasing concentration of co2