Metallic Character of the Elements: How it Varies in the Periodic Table, Properties, Element of Lesser and Greater Metallic Character

He metallic character of the elements of the periodic table refers to all those variables, chemical and physical, that define metals or distinguish them from other substances of nature. They are generally bright, dense, hard solids, with high thermal and electrical conductivities, moldable and ductile.

However, not all metals exhibit such characteristics; for example, in the case of mercury, this is a bright black liquid. Also, these variables depend on the conditions of pressure and temperature on land. For example, hydrogen, apparently non-metallic, can behave physically like a metal in extreme conditions.

These conditions can be: under abysmal pressures or very cold temperatures hovering absolute zero. To define whether an element is metallic or not, it is necessary to consider hidden patterns in the eyes of the observer: the atomic patterns.

These discriminate with greater precision and reliability which are the metallic elements, and even which element is more metallic than another. In this way, the true metallic character of a gold coin rests more on the qualities of its atoms than those determined by its golden mass, yet both are closely related.

Which of the coins is more metal: one gold, one copper or one platinum? The answer is platinum, and the explanation lies in its atoms.

How does the metallic character of the elements vary in the periodic table?

In the upper image we have the periodic properties of the elements. The rows correspond to the periods and the columns correspond to the groups.

The metallic character decreases from left to right, and increases in the opposite direction. Also, it increases from top to bottom and decreases as the periods are traversed to the group heads. The diagonal blue arrow on the table indicates the above mentioned.

In this way, the elements that are close to the direction to which the arrow points have a greater metallic character than those located in the opposite direction (the yellow blocks).

Additionally, the other arrows correspond to other periodic properties, which define in which direction they increase or decrease as the element"metallizes". For example, the elements of the yellow blocks, although they have low metallic character, their electronic affinity and ionization energy are high.

In the case of atomic radios, the larger they are, the more metallic the element is; This is indicated by the blue arrow.

Properties of metallic character elements

In the periodic table it is observed that metals have large atomic radii, low ionization energies, low electronic affinities and low electronegativities. How to memorize all these properties?

The point at which they flow is the reactivity (electropositivity) that defines the metals, which are oxidized; that is, they lose electrons easily. When they lose electrons, metals form cations (M ⁺ ). Therefore, elements with greater metallic character form cations with greater ease than those with a smaller metallic character.

An example of the above is to consider the reactivity of the elements of group 2, the alkaline earth metals. Beryllium is less metallic than magnesium, and this in turn is less metallic than calcium. So on until you get to the barium metal, the most reactive of the group (after the radio, radioactive element).

How does atomic radio affect the reactivity of metals?

As the atomic radius increases, valence electrons are further away from the nucleus, so they are retained with less force in the atom.

However, if you go through a period to the right side of the periodic table, the nucleus adds protons to your body, now more positive, which attracts more strongly valence electrons, reducing the size of the atomic radius. This results in a decrease in the metallic character.

Thus, a very small atom with a very positive nucleus tends to gain electrons instead of losing them (non-metallic elements), and those that can both gain and lose electrons are considered metalloids. Boron, silicon, germanium and arsenic are some of these metalloids.

On the other hand, the atomic radius also increases if there is new energy availability for other orbitals, which occurs when descending into a group. For this reason, when descending in the periodic table, the radii become voluminous and the nucleus becomes incapable of preventing other species from snatching the electrons from its outer layer.

In the laboratory, with a strong oxidizing agent - such as diluted nitric acid (HNO) ₃ ) - the reactivities of metals against oxidation can be studied. In the same way, the processes of formation of their metallic halides (NaCl, for example) are also demonstrative experiments of this reactivity.

Element of greater metallic character

The direction of the blue arrow in the image of the periodic table leads to the elements francio and cesium. The francium is more metallic than the cesium, but unlike the latter, the francium is artificial and radioactive. For this reason, cesium occupies the place of the natural element of greater metallic character.

In fact, one of the most known (and explosive) reactions known is that which occurs when a piece (or drops) of cesium come into contact with water. The high reactivity of cesium, also translated into the formation of much more stable compounds, is responsible for the sudden release of energy:

2Cs (s) + 2H ₂ O → 2CsOH (aq) + H ₂ (g)

The chemical equation allows to see the oxidation of cesium and the reduction of hydrogen from water to gaseous hydrogen.

Element of smaller metallic character

On the opposite diagonal, in the upper right corner of the periodic table, fluorine (F ₂ , top image) leads the list of non-metallic elements. Why? Because it is the most electronegative element in nature and the one with the lowest ionization energy.

In other words, it reacts with all the elements of the periodic table to form the ion F ^- and not F ⁺ .

Fluorine is very unlikely to lose electrons in any chemical reaction, quite the opposite of metals. It is for this reason that it is the element of least metallic character.

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