Assume that a hydrogen atom's electron has been excited to the n 5 level. how many different wavelengths of light can be emitted as this excited atom loses energy?

From n = 5, the electron can drop to n = 4, 3, 2, 1 . Thus, there will be 4 possibilities

Now, the electron that dropped to n = 4 can drop to n = 3, 2, 1. This will give 3 possibilities

The electron at n = 3, can drop to n = 2, 1. This gives 2 possibilities

Finally, the electron at n = 2 can drop to n=1. This gives 1 possibility

Thus in total the number of ways in which the electron can de-excite is :

4+3+2+1 = 10

10 different wavelengths of light can be emitted as the electron loses energy from n = 5 level

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.