What type of particle is helium and what is it a nucleus of? !

Zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a? a. a compound b. an element c. a heterogeneous mixture d. a homogeneous mixture

What are the 4 phases of matter in order of increasing engery content?

In 2002, the rare earth elements mine in mountain pass, california was closed because