The atomic number of an element is equal to the number of protons in each atom of the element. All helium atoms have 2 protons. What is the atomic number of helium?

Explain this difference in reactivity between an ammonium ion and an iminium ion.

What could J. J. Thomson conclude from his experiments? Atoms are mostly empty space. Most of the mass of the atom is concentrated in the center. Atoms must balance positive and negative particles. Atoms are indivisible.

If you need to do a 1:20 dilution on a culture to get acceptable plate counts, how many milliliters of original sample will you add to a final volume of 0.1 mL? For this course, a 1:20 dilution is 1 part culture to a final volume of 20 parts.

How many molecules of water make up 5 moles?

What volume of oxygen gas is released at STP if 10.0 g of potassium chlorate is decomposed? (The molar mass of KClO3 is 122.55 g/mol.)

Which one doesnt belong in the list below? A. a meter B. one liter C. One centimeter D. one kilometer

Which elements did curies discover

When rubidium metal is exposed to air, two atoms of rubidium, Rb, combine with one atom of oxygen. If 1.98 grams of rubidium is exposed to air, what will be the mass of the product in grams

Fission reactions can get of of control without what taking place?

In which main energy level does the 's' sublevel first appear? K (first main energy level) L (second main energy level) M (third main energy level) N (fourth main energy level)