Introduction:

Helium walks into a bar,

The bartender says "We don't serve noble gasses in here."

Helium doesn't react.

Q: What did Michael Jackson say when he found 2 isotopes of helium?

A: HeHe

The energy required to remove one electron from a neutral atom of an element.

Ionization energy tends to increase throughout the periodic table as it goes up and to the right of the table. As elements are in the further left side of the periodic table, they tend to lose electrons because the attraction is not strong.

Ionization

Ionization in the real world 

When sodium and chlorine combine to make salt, the sodium atom gives up an electron resulting in a positive charge while chlorine gets the electron and becomes negatively charged. 

Electronegativity

Electronegativity measures the tendency of an atom to attract a shared pair of electrons. An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons live from the charged nucleus.

Examples of Electronegativity

Sodium has an electronegativity of 0.9, while chlorine has an electronegativity of 3.0. 

This means that it has an ionic bond since the difference between the sodium and chlorine is 2.1

The atomic radius is the distance between the atomic nuclei. On the periodic table the farther to the top right you get the lower the radius. The closer to the bottom left the element is the larger the radius

ATOMIC RADIUS