Arrange the following atoms in order of increasing effective nuclear charge experienced by the electrons in the n = 3 electron shell: K,Mg,P,Rh,and Ti.

I think that the effective nuclear charge increases as you go up a group and across a period.

so Rh, K, Ti, Mg, P?

To determine the order of increasing effective nuclear charge experienced by the electrons in the n = 3 electron shell of the given atoms, you can consider the periodic trends.

Effective nuclear charge refers to the attractive force that the positively charged nucleus exerts on the electrons in an atom's electron shell. It depends on both the nuclear charge (number of protons) and the shielding effect caused by inner electron shells.

In general, as you move across a period from left to right, the effective nuclear charge increases. This is because the number of protons in the nucleus increases, while the shielding effect remains relatively constant. As you go down a group, the effective nuclear charge tends to increase due to the increase in the number of protons.

Let's analyze each atom provided:

K (Potassium) - It is in Group 1 (alkali metals) and Period 4. Going from left to right across Period 4, the effective nuclear charge increases.

Mg (Magnesium) - It is in Group 2 (alkaline earth metals) and Period 3. Going from left to right across Period 3, the effective nuclear charge increases.

P (Phosphorus) - It is in Group 15 (p-block) and Period 3. Going from left to right across Period 3, the effective nuclear charge increases.

Rh (Rhodium) - It is in Group 9 (d-block) and Period 5. Going from left to right across Period 5, the effective nuclear charge increases.

Ti (Titanium) - It is in Group 4 (d-block) and Period 4. Going from left to right across Period 4, the effective nuclear charge increases.

Based on the analysis, the correct order of increasing effective nuclear charge experienced by the electrons in the n = 3 electron shell is:

Mg < K < Ti < P < Rh

You are correct that the effective nuclear charge generally increases as you go up a group and across a period. However, there are a couple of things to consider in this case.

First, let's review the electron configuration of each element:

- K (Potassium): [Ar] 4s1
- Mg (Magnesium): [Ne] 3s2
- P (Phosphorus): [Ne] 3s2 3p3
- Rh (Rhodium): [Kr] 4d8 5s1
- Ti (Titanium): [Ar] 3d2 4s2

Now, when considering the effective nuclear charge experienced by the electrons in the n = 3 electron shell, we need to compare the number of protons and the shielding effect from inner shells.

Based on this, the order of increasing effective nuclear charge experienced by the electrons in the n = 3 electron shell is:

P (Phosphorus) < Ti (Titanium) < Mg (Magnesium) < Rh (Rhodium) < K (Potassium)

So, the correct order is: P, Ti, Mg, Rh, K.