On a periodic table, an element classified as a semimetal (metalloid) can be found in a. period 6, group 15 b. period 2, group 14 c. period 3, group 16 d. period 4, group 15

Which function is performed by earths atmosphere? a. ultraviolet rays are prevented from reaching the ozone layer. b. earths temperature is raised and moderated by trapping in heat c. charged particles from the sun are prevented from reaching earth. d. magnetic charges from space are prevented from reaching earths surface.

Achange in the number of neutrons in an atom will change an blank . when the number of protons changes in an atom, a new element will form.

What is the atomic mass of an atom that has 6 protons, 6 neutrons, and 6 electrons? a) 6 b) 8 c) + 1 d) 12 e) 18