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