Periodic Table Template printable pdf download

NOTES: The Modern Periodic Table

Our modern day periodic table is expanded beyond Mendeleev's. Most of the current periodic tables include 109 or

110 elements. It is also important to notice how the modern periodic table is arranged. In examining the modern

periodic table, one notices the chemical elements arranged in groups and periods. They are classified by their

general physical and chemical properties into their groups: metals, metalloids, and nonmetals, which can be further

subdivided. These classifications help chemical researchers understand known elements and predict the properties

of new manmade elements.

GROUPS

The modern periodic table of the elements contains 18 groups, or vertical columns. Elements in a group have

similar chemical and physical properties because they have the same number of outer valence electrons. Elements

in a group are like members of a family--each is different, but all are related by common characteristics. Notice that

each group is numbered from one to eighteen.

PERIODS

Each of the table's horizontal rows is called a period. The periodic table consists of seven periods. Along a period,

gradual changes in chemical properties occur from one element to another. For example, metallic properties

decrease and nonmetallic properties increase as you go from left to right across a period. Changes in the properties

occur because the number of protons and electrons increases from left to right across a period or row. The increase

in number of electrons is important because the outer electrons determine the element's chemical properties.

METALS

The vast majority of the known elements are metals. Common examples are copper, lead, silver and gold. In

general, metals have a luster, are quite dense, and are good conductors of heat and electricity. They tend to be

soft, malleable and ductile (meaning that they are easily shaped and can be drawn into fine wires without

breaking). All of these properties, called metallic properties, are directly related to the fact that the electrons that

surround the atoms of metals are highly mobile – they wander from atom to atom. This mobility allows electrons

reflect light giving the metals their typical luster (shininess). It also permits electrons to absorb heat and electrical

energy and transfer this energy to other electrons; in this way, heat and electricity can be conducted throughout the

metal. Generally speaking, the most metallic metals are in the bottom left corner. As you move toward the upper

right on the periodic table, elements become less metallic in property.

ALKALI METALS

Alkali metals (Group 1) are so chemically reactive that they are never found in pure element form in nature. This is

because they have one valence electron which is easily lost, causing the atoms to join with other atoms in order to

balance the charges. All these metals react spontaneously with gases in the air, so they must be kept immersed in

oil for storage. They are so soft that they can be cut with an ordinary table knife, revealing a very "buttery," silvery

metal surface that immediately turns dull as it reacts with water vapor and oxygen in the air. They most commonly

form compounds with halogen non-metals. The chemical reactivity of alkali metals increases as the atomic number

increases.

ALKALINE EARTH METALS

The alkaline earth metals (Group 2) also exhibit the typical metal characteristics of high density, metallic luster, and

electrical and thermal conductivity. Alkaline earth elements form compounds by losing, or in the case of beryllium,

sharing two electrons per atom. These atoms hold their electrons more tightly than alkali metals and are, therefore,

not so chemically reactive as the alkali metals. They do not require special storage because the surface of these

metals reacts with air, forming a tightly adhering layer that protects the metal and prevents additional reactions.

The chemical reactivity of these elements also increases with size of atomic number.

TRANSITION METALS

The transition (or heavy) metals have most of the usual properties of metals. Their densities are greater than the

Group 1 and 2 metals. The transition metals are also called heavy metals because their atoms have large numbers

of protons and neutrons to give them relatively large masses. One of the main uses for transition metals is the

formation of alloys—mixtures of metals—to produce tools and construction materials for specific uses. Copper,

silver and gold are sometimes known as coinage metals because they can be found naturally in pure form and

because they tarnish slowly. Since prehistoric times, they have been used in coins, utensils, weapons, and jewelry.

Most transition metals have very high melting and boiling points; mercury (Hg) though has such a low melting point

that it is a liquid at room temperature. All the transition metals are electrical conductors, with copper, silver and gold

being among the best; they are also good heat conductors.

Periodic Table Template

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