Mendeleev arranged the elements according to their atomic masses
<span>The movement of particles within a solid is extremely slow when compared to that of a gas. It is also significantly slower in movement than that of the movement found within the particles of liquid. The more movement present and the faster the movement of the particles the more space will be present between each particle. This causes the material to spread out as they become less densely packed within a solid material.</span>
Answer:
The answer to your question is
1.- 1.686 x 10²⁴ atoms
2.- 0.25 moles
Explanation:
1.-
1 mol ---------------- 6.023 x 10²³ atoms
2.8 moles ---------- x
x = (2.8 x 6.023 x 10²³) / 1
x = 1.686 x 10²⁴ atoms
2.- 1 mol ------------------ 6.023 x 10 ²³ molecules
x moles ------------- 1.50 x 10²³ molecules
x = (1.50 x 10²³ x 1) / 6.023 x 10²³
x = 0.25 moles