Question

what has the greatest atomic radius?
he
cl
sr
cs
what has the greatest ionic radius?
he
cl
sr
cs
what has the greatest ionization energy?
he
cl
sr
cs
what has the greatest electronegativity?
he
cl
sr
cs

Explanation:

1. Atomic Radius: Atomic radius increases down a group and decreases across a period. Cs (Cesium) is in Group 1 and Period 6, He (Helium) is in Group 18 and Period 1, Cl (Chlorine) is in Group 17 and Period 3, Sr (Strontium) is in Group 2 and Period 5. Cs has the most electron - shells among them, so it has the largest atomic radius.
2. Ionic Radius: Cs forms a + 1 ion. When an atom forms a cation, the ionic radius is generally smaller than the atomic radius, but among these elements, Cs has a large atomic size to start with and its ion still has a relatively large radius compared to the others considering their positions in the periodic table.
3. Ionization Energy: Ionization energy decreases down a group and increases across a period. He has a full - shell electron configuration (1s²) and is in the top right of the periodic table (noble gas), so it has a very high ionization energy. Cs is in the bottom left, so it has a low ionization energy.
4. Electronegativity: Electronegativity increases across a period and decreases down a group. Cl is a non - metal and has a relatively high electronegativity. Cs is a metal with low electronegativity, He is a noble gas and does not readily form compounds so its electronegativity is not considered in the traditional sense.

Answer:

1. What has the greatest Atomic Radius? Cs
2. What has the greatest Ionic Radius? Cs
3. What has the greatest Ionization Energy? He
4. What has the greatest Electronegativity? Cl