First Ionization EnergyAtomic radiusElectronegativityPhysical PropertiesThe metallic frameworks

This page describes and also explains the fads in atomic and also physical nature of the period 3 elements from sodium to argon. That covers ionization energy, atom radius, electronegativity, electric conductivity, melting allude and boiling point.

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First Ionization Energy

The first ionization power is the power required to remove the most loosely held electron indigenous one mole the gaseous atom to develop 1 mole that gaseous ions each with a fee of +1.

\< X (g) \rightarrow X^+ (g) + e^-\>

The molar very first ionization energy is the energy required to carry out this change per mole the \(X\).

The sample of an initial ionization energies across duration 3


There is a general upward trend throughout the period, however this trend is damaged by decreases between magnesium and also aluminum, and also between phosphorus and also sulfur.

Atomic radius

The diagram below shows just how atomic radius alters across duration 3.


Explaining the Trend

The explanation is the same as the for the tendency in atom radii. Across the period, the valence electrons because that each atom are in the 3-level. They space screened by the exact same inner electrons. The only difference is the variety of protons in the nucleus. From salt to chlorine, the variety of protons steadily increases and so attractive the bonding pair much more closely.

Structures of the elements

The frameworks of the aspects vary throughout the period. The first three room metallic, silicon is network covalent, and the rest are an easy molecules.

Three metallic structures

Sodium, magnesium and also aluminum all have actually metallic structures. In sodium, only one electron per atom is associated in the metallic bond, the single 3s electron. In magnesium, both of its outer electrons room involved, and in aluminum all three are involved. One key difference to be conscious of is the way the atoms room packed in the steel crystal. Sodium is 8-coordinated v each sodium atom connecting with only 8 other atoms. Magnesium and aluminum are each 12-coordinated, and therefore packed much more efficiently, producing less empty an are in the metal structures and also stronger bonding in the metal.

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A network covalent structure

Silicon has a network covalent structure choose that the diamond. A representative section of this structure is shown:


The structure is hosted together by strong covalent bond in all three dimensions.

Four an easy molecular structures

The frameworks of phosphorus and sulfur vary depending on the kind of phosphorus or sulfur in question. In this case, white phosphorus and one that the crystalline develops of sulfur—rhombic or monoclinic—are considered. These frameworks are displayed below: