Periodicity: Looking at the below diagram you will see a red stair- step line. This is the periodic table’s dividing line. On the left side of the line you will find the metals (with the exception of hydrogen). On the right side of the line you will find the non-metals. Those elements touching this stair-step line are considered metalloids. Metalloids have properties of both metals and non-metals

Atomic Radii 1) As you move down a group, atomic radius increases. The number of energy levels increases as you move down a group as the number of electrons increases.  Each subsequent energy level is further from the nucleus than the last.  Therefore, the atomic radius increases as the group and energy levels increase.  2) As you move across a period, atomic radius decreases. As you go across a period protons are being added to the nucleus.  The concentration of more protons in the nucleus creates a "higher effective nuclear charge."  In other words, there is a stronger force of attraction pulling the electrons closer to the nucleus resulting in a smaller atomic radius

First Ionization Energy Definition:  The energy required to remove the outermost (highest energy) electron from a neutral atom in its ground state. Li → Li+ + e- 1) As you move down a group, first ionization energy decreases. Electrons are further from the nucleus and thus easier to remove the outermost one. 2) As you move across a period, first ionization energy increases. As you move across a period, the outer electrons are closer to the nucleus because they are more strongly attracted to the center. Accordingly, it becomes more difficult to remove the outermost electron.

Electron Affinity F + e- → F- Definition:  The energy released when a neutral atom in the gas phase gains an extra electron to form a negatively charged ion F + e- → F- As you move down a group, electron affinity decreases. the electron being added to the atom is placed in a larger orbital so the force of repulsion between the electron being added and the electrons already present on a neutral atom becomes larger 2) As you move across a period, electron affinity increases. as you move across a period, the number of protons pulling in the electron increases, thus force of attraction increases

Electronegativity Definition:  a measure of the tendency of an atom to attract electrons when bonding As you move down a group, electronegativity decreases. the electron(s) being attracted in the valence shell is further from the nucleus 2) As you move across a period, electronegativity increases. as you move across a period, the number of protons attracting the electron(s) increases, thus force of attraction increases

atomic radius increases electron affinity increases * atomic radius increases electron affinity increases * ionization energy increases electronegativity increases metallic character increases * Irrespective of the noble gases