Is the periodic table of the elements all of the atoms known to exist?

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.

How can you write e method for the experiment of separating sand from water by filtration process? 1-materials 2-steps 3-conclusion also the same for the separating process of water and salt by filtration or distillation. quick because i need to finish my hw