Periodic Trends

Ionization Energy (IE)

Electron affinity

Effective nuclear charge

Atomic Radius

Definition: The amount of energy required to remove the outermost electron on the valence shell out of the atom/ion in the gaseous state.

There are two types of Ionization Energy (IE):

Formula

Electronegativity

The attractive force of the nucleus felt by the outermost valence electrons.

The atomic radius of an atom is the measure of the distance from the center of the nucleus to the outer electron shell

Zeff = (# protons of element) - (# shielding electrons before the outermost valance shell's electrons)

A measure of the ability of an atom to attract electrons towards it when it is an covalent bond

Decreases from top to bottom(down a group)

Across a period, effective nuclear charge increases as electron shielding remain constant (increases from left to right).

The atomic radius of an atom increases when the number of electrons in the outer shell of an atom increases

Increases from left to right (within a period)

First Ionization Energy (IE1): the energy required to remove the first (outermost) electron from an atom in the gaseous state.

Second Ionization Energy (IE2): the energy required to remove the second electron from an ion that has already lost one electron.

The radius increases from left to right


Going down a group, distance and shielding increase, therefore effective nuclear charge decreases (increases from bottom to top).

First IE: A(g) + energy → A+(g) + e-

Second IE: A(g) + energy → A2+(g) + e-

General: A(g) + energy → A+(g) + e-

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The radius increases from up to down

Energy that is absorbed or released when a single electron is added to a neutral atom in the gaseous state

Trends

When the atomic number of the atom increases, the number of protons and electrons Increase as well. Therefore, there will be more electron shells, causing the radius to increase

In a group: Increases as it goes from top to bottom

In a period: Increases as it goes from left to right

EA becomes increasingly negative as you go across a period

EA becomes increasingly negative as you go up a group

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The atomic radius of an atom will increase from left to right as a fuller valence shell means that the atoms have a stronger electromagnetic attraction making it more compacted

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