Why do representative elements form ions

Metals among the representative elements are the representative metals. The radioactive elements copernicium, flerovium, polonium, and livermorium are also metals but are beyond the scope of this chapter. Nonmetals are shown in green, metalloids in purple, and the transition metals and inner transition metals in blue.

In addition to the representative metals, some of the representative elements are metalloids. A metalloid is an element that has properties that are between those of metals and nonmetals; these elements are typically semiconductors. The remaining representative elements are nonmetals.

Unlike metals , which typically form cations and ionic compounds containing ionic bonds , nonmetals tend to form anions or molecular compounds. In general, the combination of a metal and a nonmetal produces a salt. A salt is an ionic compound consisting of cations and anions. Most of the representative metals do not occur naturally in an uncombined state because they readily react with water and oxygen in the air.

However, it is possible to isolate elemental beryllium, magnesium, zinc, cadmium, mercury, aluminum, tin, and lead from their naturally occurring minerals and use them because they react very slowly with air. Part of the reason why these elements react slowly is that these elements react with air to form a protective coating. The formation of this protective coating is passivation. The coating is a nonreactive film of oxide or some other compound.

Elemental magnesium, aluminum, zinc, and tin are important in the fabrication of many familiar items, including wire, cookware, foil, and many household and personal objects. Although beryllium, cadmium, mercury, and lead are readily available, there are limitations in their use because of their toxicity. The alkali metals lithium, sodium, potassium, rubidium, cesium, and francium constitute group 1 of the periodic table. Although hydrogen is in group 1 and also in group 17 , it is a nonmetal and deserves separate consideration later in this chapter.

The name alkali metal is in reference to the fact that these metals and their oxides react with water to form very basic alkaline solutions. The properties of the alkali metals are similar to each other as expected for elements in the same family. The alkali metals have the largest atomic radii and the lowest first ionization energy in their periods.

This combination makes it very easy to remove the single electron in the outermost valence shell of each. Their reactivity increases with increasing atomic number due to the ease of losing the lone valence electron decreasing ionization energy. Since oxidation is so easy, the reverse, reduction, is difficult, which explains why it is hard to isolate the elements.

The alkali metals all react vigorously with water to form hydrogen gas and a basic solution of the metal hydroxide. This means they are easier to oxidize than is hydrogen. As an example, the reaction of lithium with water is:.

These metals are so reactive that it is necessary to avoid contact with both moisture and oxygen in the air. The pure metals never exist free uncombined in nature due to their high reactivity. In addition, this high reactivity makes it necessary to prepare the metals by electrolysis of alkali metal compounds.

Unlike many other metals, the reactivity and softness of the alkali metals make these metals unsuitable for structural applications. However, there are applications where the reactivity of the alkali metals is an advantage. For example, the production of metals such as titanium and zirconium relies, in part, on the ability of sodium to reduce compounds of these metals.

The manufacture of many organic compounds, including certain dyes, drugs, and perfumes, utilizes reduction by lithium or sodium. Passing an electrical discharge through sodium vapor also produces this color. In both cases, this is an example of an emission spectrum as discussed in the chapter on electronic structure.

Streetlights sometime employ sodium vapor lights because the sodium vapor penetrates fog better than most other light. This is because the fog does not scatter yellow light as much as it scatters white light. The other alkali metals and their salts also impart color to a flame.

Lithium creates a bright, crimson color, whereas the others create a pale, violet color. The alkaline earth metals beryllium, magnesium, calcium, strontium, barium, and radium constitute group 2 of the periodic table.

The name alkaline metal comes from the fact that the oxides of the heavier members of the group react with water to form alkaline solutions. The nuclear charge increases when going from group 1 to group 2. Because of this charge increase, the atoms of the alkaline earth metals are smaller and have higher first ionization energies than the alkali metals within the same period.

They lose 2 electrons. Explanation: As you know, neutral atoms become ions by losing or by gaining electrons. Related questions How can the periodic table be used to predict new elements? How are the elements are organized in the periodic table? Why is the periodic table a useful tool? As demonstrated here, a sodium atom Na has one valence electron in the third principal energy level.

It is likely to achieve an octet in its outermost shell by losing its one valence electron. It is now the same as that of the noble gas neon. The term isoelectronic refers to an atom and an ion of a different atom or two different ions that have the same electron configuration.

The sodium ion is isoelectronic with the neon atom. The equation below illustrates this process. When a chlorine atom gains an electron, its outermost principal energy level achieves an octet. In this case, the ion has the same outermost shell as the original atom, but now that shell has eight electrons in it.

Once again, the octet rule has been satisfied. This process is illustrated below. In table salt, this electron comes from the sodium atom. With two oppositely charged ions, there is an electrostatic attraction between them because opposite charges attract. The resulting combination is the compound sodium chloride.

Notice that there are no leftover electrons. The number of electrons lost by the sodium atom one equals the number of electrons gained by the chlorine atom one , so the compound is electrically neutral. In macroscopic samples of sodium chloride, there are billions and billions of sodium and chloride ions, although there is always the same number of cations and anions.

Write the formula of the resulting ion and its electron configuration. The electron configuration of Al atom is 1 s 2 2 s 2 2 p 6 3 s 2 3 p 1. The second shell has octet 2 s 2 2 p 6 while the valence shell has 3 electrons 3 s 2 3 p 1. Mg can achieve octet by losing the 3 valence electrons.

The electron configuration of O atom is 1 s 2 2 s 2 2 p 4. The second shell has six electrons 2 s 2 2 p 4 and needs two electrons to achieve octet. When molten, however, it can conduct electricity because its ions are able to move freely through the liquid Figure 3. Figure 3. Many compounds do not contain ions but instead consist solely of discrete, neutral molecules.

These molecular compounds covalent compounds result when atoms share, rather than transfer gain or lose , electrons. Covalent bonding is an important and extensive concept in chemistry, and it will be treated in considerable detail in a later chapter of this text. We can often identify molecular compounds on the basis of their physical properties.

Under normal conditions, molecular compounds often exist as gases, low-boiling liquids, and low-melting solids, although many important exceptions exist. Whereas ionic compounds are usually formed when a metal and a nonmetal combine, covalent compounds are usually formed by a combination of nonmetals.

Thus, the periodic table can help us recognize many of the compounds that are covalent. Metals particularly those in groups 1 and 2 tend to lose the number of electrons that would leave them with the same number of electrons as in the preceding noble gas in the periodic table.

By this means, a positively charged ion is formed. Similarly, nonmetals especially those in groups 16 and 17, and, to a lesser extent, those in Group 15 can gain the number of electrons needed to provide atoms with the same number of electrons as in the next noble gas in the periodic table. Thus, nonmetals tend to form negative ions. Positively charged ions are called cations, and negatively charge ions are called anions. Ions can be either monatomic containing only one atom or polyatomic containing more than one atom.

Compounds that contain ions are called ionic compounds. Ionic compounds generally form from metals and nonmetals. Compounds that do not contain ions, but instead consist of atoms bonded tightly together in molecules uncharged groups of atoms that behave as a single unit , are called covalent compounds.

Covalent compounds usually form from two nonmetals. Privacy Policy.