Please help me and thx For the periodic table
What is a period?
Define a family / group ?
With own word please and thx

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Why did southern business leaders want to increase the number of slaves

Which common material is an example of a polymer? (25 pts) a. steel b. plastic c. petroleum d. rubbing alcohol