What element has 12 protons, 12 neutrons and 12 electrons?

This active feature of earth's crust in building mountain ranges as well as islands. this feature is a a) cavern. b) earthquake. c) mountain. d) volcano.

How many moles of no2 will form when 3.3 moles of cu are reacted with excess hno3?

Quickly what are the following of organisms that existed over a wide area but only for a limited time period called a.soft fossils b.mold fossils c.index fossils d.trace fossils