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.

C

Explanation:

your cleaning items have chemicals batteries have chemicals.

not clear

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.