Answer:
25th electron
Explanation:
the last electron is the valence electron. Assuming it has equal numbers of protons and electrons, then the 25th electron is the valence.
Answer:
n = 3
Explanation:
Given the formula for the transition energy of an atom with 1 electron:

For the H transition n=5 to n=2:

Then we solve for nf with Z=2 (Helium)


Is near 3, actually the energy of the transitions are:
H (5⇒2) = -2.85 eV = 434 nm (Dark blue)
He (4⇒3) = -2.64 eV = 469 nm (Light blue)
I thought it was cool to see the actual colors. Included them.
Answer: Plate movement is thought to be driven by a combination of the motion of the seafloor away from spreading ridges due to variations in topography and density changes in the crust.
Hope this helps
Answer:
breaking glass
Explanation:
breaking glass cant be reversed