order Se, S, As, by increasing atomic radius? explain why?
I would go with S, As, Se.
Look at the periodic table. S is one row up so everything S has extra shells which means larger.
As and Se are consecutive in the table. Se contains one more proton and 1 more electron but no more shells. Therefore, I would expect the Se to be slightly smaller because of the extra proton attracting outside electrons.
To order Se, S, As by increasing atomic radius, we need to compare the atomic radii of these elements.
Atomic radius generally increases as you move down a group (vertical column) in the periodic table. This is because each row or period in the periodic table adds a new electron shell, increasing the distance between the nucleus and the outermost electrons.
Based on this information, we can analyze the elements in question:
1. Sulfur (S) is in the 3rd period, specifically in group 16. Atomic radius increases as we move down a group, so Sulfur has a larger atomic radius compared to the next element.
2. Selenium (Se) is in the 4th period, also in group 16. Since it is below Sulfur, its atomic radius is expected to be larger.
3. Arsenic (As) is in the 4th period as well, but it is one period below Sulfur and Selenium. Therefore, it is expected to have the largest atomic radius among the three elements.
So, the ordered list of elements based on increasing atomic radius is As, Se, S.
To order Se (Selenium), S (Sulfur), and As (Arsenic) by increasing atomic radius, you need to compare the sizes of their respective atoms. Atomic radius refers to the distance from the nucleus to the outermost electron shell of an atom, and it increases as you move down a group in the periodic table and from right to left across a period.
Let's break down the explanation step by step:
1. Locate the elements on the periodic table:
- Selenium (Se) is located in Group 16, Period 4.
- Sulfur (S) is also located in Group 16, Period 3.
- Arsenic (As) is located in Group 15, Period 4.
2. Compare the periods:
- The period number corresponds to the outermost electron shell. Since both Selenium and Arsenic are in Period 4, the comparison will depend on the group number. However, Sulfur is in Period 3, so it will likely have a smaller atomic radius compared to the other two elements.
3. Compare the groups:
- As you move down a group, the atomic radius tends to increase because additional electron shells are added. Since Selenium and Arsenic are in the same group (Group 16), the comparison will depend primarily on the effective nuclear charge.
4. Consider the effective nuclear charge:
- The effective nuclear charge refers to the attractive force between the protons in the nucleus and the electrons in the outermost valence shell. It increases from left to right across a period, and it affects the shielding of the outer electrons.
- In this case, Selenium (Se) has a smaller effective nuclear charge than Arsenic (As) because Se is to the left of As in the same period. Therefore, Se has a larger atomic radius than As.
Based on this analysis, the correct order of the elements by increasing atomic radius is: S (Sulfur) < Se (Selenium) < As (Arsenic).