Ionization energy goes up across the period and down as you go down the group. This is the energy required to remove an electron. Of the listed elements it would be hardest to remove an electron from Flourine as the positive nucleus close to the electron orbitals has greater attractive force.

Helium has the smallest atomic radius. This is due to trends in the periodic table, and the effective nuclear charge that holds the valence electrons close to the nucleus. Atomic radius decreases as you move across a period from left to right and decreases as you move up a group from bottom to top. Since He is at the upper right-hand corner of the table, it must have the smallest atomic radius.

The periodic table allows you to follow general guidelines or "trends" that are displayed on the table. Atomic radius is one such trend. As you move down in groups, further shells are added to the atom which results in an increase in radius. As you move to the right on the periodic table, the nuclear charge increases which pulls the elctrons closer to the nucleus. As a result, the atomic radius will decrease when moving to the right.

Atomic radius decreases as you move left to right on the periodic table. As atomic number increases, so does the number of positive protons in the nucleus. To the far left of a period, electrons are widespread within a new electronic shell. To the far right of the period, the electrons still occupy the same shell, but experience greater attractive force toward the nucleus due to the higher number of protons present.

While it is true that flourine is the most electronegative element, this does not influence atomic radius (though the two trends follow similar patterns).

The atomic radius of elements decreases as one moves from left to right across the periodic table. The degree to which lithium has a larger atomic radius than fluorine is most similar to the difference between another pair of elements within the same groups, that are also found on the left and right sides of the table.

Fluorine and chlorine are both halogens, and lithium and sodium are both alkali metals. Fluorine and lithium are both in the second period, and sodium and chlorine are both in the third. As you move from lithium to fluorine across the table, you will see similar changes and patterns as if you were moving from sodium to chlorine.

When predicting how atomic radius will change as you move along the periodic table, remember these two trends.

1. As you move down the table in a given group, the atomic radius of the atoms will increase.

2. As you move left to right in a given period, the atomic radius will decrease.

Knowing this, we can compare the possible options. Sulfur and chlorine are in the lowest period, so they have the largest atomic radii. Because sulfur is to the left of chlorine on the periodic table, it will have a larger atomic radius. As a result, sulfur has the largest atomic radius out of the possible options.

As you move across a single period (row) on the periodic table, the atomic radius of each successive atom decreases. As you move down a single group (column), the atomic radius of each successive atom increases. As you move down a group, the maximum energy level of the valence shell increases, thus increasing the size of the electron cloud and atomic radius. As you move across a period to the right, the number of protons in the nucleus increases. This also increases the attraction between the positively-charged nucleus and negatively-charged electrons, pulling the electrons in tighter and reducing the atomic radius.

The smallest atoms are going to be located toward the upper right of the periodic table. Of our given answer choices, fluorine is the closest to the upper right, and thus has the smallest radius.

Atomic radius will decrease as you move to the right, because the atomic number of the element will be increasing. This results in a more positively charged nucleus that pulls the electrons closer to the center. As a result, atomic radius will notably decrease from left to right.

Electronegativity, ionization energy, and electron affinity all increase to the right of the periodic table.

Within the same period of the periodic table, atomic radii decrease as there are more charged particles to attract one another, and within the same group, atomic radii increases. The increase from the ascending group generally speaking is larger than the decrease down a period.

Four of the elements listed are within the same period, so we will place those four elements in order of decreasing atomic radii:

Now we simply have to place Neon, Fluorine, and Oxygen, which are in the same period. The trend of decreasing radii with increasing atomic number is not true for noble gases, as they have a complete octet and are slightly larger to offset electron-electron repulsion from the octet. In order of decreasing atomic radius:

The increase from the octet is less than the increase from electron-electron repulsion.

The alkali metals are found in the first group (column) of the periodic table, on the leftmost side. They have only 1 loosely bound electron in their outermost shells, and their effective nuclear charge values are low, giving them the largest atomic radii of all the elements in their periods.