IONIZATION ENERGY

WHAT IS IONIZATION ENERGY?

• The energy required to remove an electron from an atom
• This energy is measured when an element is in its gaseous state.
• The energy required to remove the first electron from an atom is called the first ionization energy.

FIRST IONIZATION ENERGY
- tends to decrease from top to bottom within a group and increase from left to right across a period.

Untitled Slide

As we could see in the picture, the ionization energy arrow is pointing to the right and upward. So the element on the upper rightmost side receives the highest first ionization energy.

So in this case, Helium (H) receives the highest with 2,372 on it's first ionization energy.

Group Trends in Ionization Energy

-The atomic size increases as the atomic number increases within a group.
-Less energy is required to remove an electron from this energy level and the first ionization energy is lower.

Li -520 Be -899 B-800 C-1086 N-140 O-1314 F-1680
Above^^,
Since Lithium is in the leftmost side of the periodic table, it has the lowest first ionization energy compared to the others. While Fluorine has the highest because it is at the rightmost side of the periodic table, and has the highest first ionization energy compared to the others.

Li 520
Na 496
K 419
Rb 408
Cs 376
Fr 398
Above^^
Since Francium is at the bottom left part of the periodic table, it receives the lowest first ionization energy compared to the others. For Lithium, it is the highest.

References:
http://chemwiki.ucdavis.edu/Physical_Chemistry/Physical_Properties_of_Matte...