Rank these elements according to first ionization energy..

I ranked them like this Ar Cl S P Si Al Mg Na but then it tells me that two elements should move up one spot in the ranking because of stable electrons configurations. Which ones would be moved up and why?

To rank the elements according to first ionization energy, you need to consider the trend in ionization energy across the periodic table. Generally, ionization energy increases from left to right within a period and decreases from top to bottom within a group.

So, let's analyze the elements you provided and determine which ones should be moved up one spot based on stable electron configurations:

1. Ar (Argon) - The noble gases have very high ionization energies since their electron configurations are already stable. So, Ar should be ranked first.

2. Cl (Chlorine) - Chlorine is in the halogen group, which is close to achieving a stable electron configuration by gaining one electron. Therefore, it should be ranked second.

3. S (Sulfur) - Sulfur is also in the same group as chlorine and has a similar tendency to gain one electron. It should be ranked third.

4. P (Phosphorus) - Phosphorus is in the group above sulfur and chlorine. Although it is approaching a stable electron configuration, its ionization energy is slightly lower than sulfur because it has a larger atomic radius. Thus, it should be ranked fourth.

5. Si (Silicon) - Silicon is in the group above phosphorus and has a similar trend in increasing ionization energy. It should be ranked fifth.

6. Al (Aluminum) - Aluminum is located in the group of metals called the p-block, and its ionization energy is higher compared to the previous elements due to its smaller atomic size. It should be ranked sixth.

7. Mg (Magnesium) - Magnesium is a group 2 (alkaline earth metal) element, so its ionization energy is lower than aluminum due to its larger atomic size. It should be ranked seventh.

8. Na (Sodium) - Sodium is in group 1 (alkali metal) and has the lowest ionization energy among the elements listed. It should be ranked last.

Therefore, the two elements that should be moved up one spot in your ranking are Phosphorus (P) and Silicon (Si).

In order to determine which elements should be moved up in the ranking, we need to look at their electron configurations and identify any exceptions to the general trend of increasing ionization energy across a period.

The electron configurations of the elements you listed are as follows:

Ar: 1s² 2s² 2p⁶ 3s² 3p⁶
Cl: 1s² 2s² 2p⁶ 3s² 3p⁵
S: 1s² 2s² 2p⁶ 3s² 3p⁴
P: 1s² 2s² 2p⁶ 3s² 3p³
Si: 1s² 2s² 2p⁶ 3s² 3p²
Al: 1s² 2s² 2p⁶ 3s² 3p¹
Mg: 1s² 2s² 2p⁶ 3s²
Na: 1s² 2s² 2p⁶ 3s¹

Based on the electron configurations, we can see that both Al and S have stable electron configurations. Al has a completely filled 3p orbital, while S has a completely filled 3p subshell.

The presence of stable electron configurations tends to make it easier to remove an electron, resulting in a lower first ionization energy. Therefore, both Al and S should be moved up in the ranking above Cl.

Corrected ranking: Ar Al S Cl P Si Mg Na

Your question should have stated if you want the IP increasing or decreasing. You have ranked them decreasing because Na must be the lowest and Ar must be the highest. I expect the two closed shell elements are Al and Mg. You can look up the first IP for each at www.webelements.com