Ionization Energy

[Andrea_1H]

How can you tell which atom has the lowest ionization energy when constructing a Lewis structure? Or just in general?

[Cassidy Kohlenberger 3D]

Use periodic trends! The atom with the lowest ionization energy takes the least amount of energy to remove a valence electron from its outer shell. Ionization energy increases from left to right across a period and decreases going down a group. This is because a larger atomic radius means the valence electrons aren't held as tightly and therefore are easier to remove. Also, elements on the far right of the periodic table don't want to give away electrons as they are almost at a full valence shell. So...when deciding which element in an atom has the least ionization energy, keep in mind how many valence electrons each one has and where they are located on the periodic table :)

[Dan M -3E]

You just have to memorize the periodic trends, with IE increasing from left to right and from top to bottom. So, Helium will have the highest ionization energy, meaning it is the least willing to lend an electron, while the bottom left atom will have the lowest, meaning it is the most willing to give an electron away because the electrons are so far from the nucleus and there is only one in the outermost shell.

[Jenna Ortiguerra 4G]

It is easier to tell which atom has the lowest ionization energy through periodic trends. Typically, ionization energy increases the higher the period and as you go from left to right on the periodic table.

[Ashley Nguyen 2L]

The best way to tell which atom has the lowest ionization energy is by memorizing the periodic trends. Ionization energy increases as you go up and to the right. This is because ionization energy is defined as the amount of energy needed to remove an electron. As you move towards the right side of the table, the elemental ions here form cations, where they receive electrons to make a full shell of electrons, which is the most stable form of the atom. As you move towards the right, the atoms have more protons, creating a greater positive charge, or nuclear charge, that strongly attracts electrons. Therefore, it requires a lot of energy to remove an electron from an atom on the right side of the table. Ionization energy decreases as you move down the table because the electrons shield each other and further out, the electrons experience less attraction to the nucleus.