Is it true three or more different atoms are necessary to call a compound a molecule

Which orbitals form a pi bond? a. the s orbital and three p orbitals b. the s orbital and two p orbitals c. overlapping p orbitals d. overlapping hybrid orbitals

What can be found in the ionosphere

How can a give a full method for the experiment of separating sand from water by filtration? 1-materials 2-steps 3-conclusion also for water and salt separated by the evaporation or distillation process