Question

A sealed, rigid l.0-liter cylinder contains He gas at STP. An identical sealed cylinder contains Ne gas at STP. These two cylinders contain the same number of(1) atoms(2) electrons(3) ions(4) protons

Answer 1

The sealed, rigid 1.0-liter cylinders containing He and Ne gases at STP will have the same number of atoms, but different numbers of protons and electrons due to their distinct atomic numbers.

Step-by-step explanation:

The question is concerned with comparing two sealed, rigid 1.0-liter cylinders, one containing helium (He) gas and the other containing neon (Ne) gas, both at standard temperature and pressure (STP). At STP, one mole of any ideal gas occupies a volume of 22.4 liters. Since the cylinders are 1.0-liter and at STP, they contain a fraction of a mole of gas, but the important point is they contain an equal number of atoms of their respective elements. The number of protons and electrons will differ between He and Ne gas because they have different atomic numbers (He has 2 protons and electrons, Ne has 10 of each), and they are neutral atoms, so they do not contain ions.

Answer 2

(1) atoms is your answer. Recall Avogadro's Law stating that all gases under STP has the same volume if there are equal number of particles.