Family Name Periodic Table Family Name Periodic Table Valence Electrons

2.5 The Periodic Table

Learning Objectives

By the end of this department, y'all will be able to:

• State the periodic law and explain the organization of elements in the periodic table
• Predict the general properties of elements based on their location within the periodic table
• Place metals, nonmetals, and metalloids by their properties and/or location on the periodic tabular array

As early chemists worked to purify ores and discovered more elements, they realized that various elements could be grouped together by their similar chemical behaviors. One such group includes lithium (Li), sodium (Na), and potassium (Chiliad): These elements all are shiny, behave estrus and electricity well, and accept like chemical properties. A second grouping includes calcium (Ca), strontium (Sr), and barium (Ba), which also are shiny, good conductors of estrus and electricity, and have chemical properties in common. Nonetheless, the specific properties of these ii groupings are notably different from each other. For example: Li, Na, and K are much more than reactive than are Ca, Sr, and Ba; Li, Na, and M course compounds with oxygen in a ratio of two of their atoms to one oxygen atom, whereas Ca, Sr, and Ba grade compounds with one of their atoms to one oxygen atom. Fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) also exhibit similar properties to each other, only these properties are drastically different from those of any of the elements above.

Dimitri Mendeleev in Russian federation (1869) and Lothar Meyer in Frg (1870) independently recognized that there was a periodic relationship among the backdrop of the elements known at that time. Both published tables with the elements arranged according to increasing atomic mass. But Mendeleev went one stride further than Meyer: He used his table to predict the existence of elements that would have the backdrop similar to aluminum and silicon, only were yet unknown. The discoveries of gallium (1875) and germanium (1886) provided great support for Mendeleev'due south piece of work. Although Mendeleev and Meyer had a long dispute over priority, Mendeleev's contributions to the development of the periodic table are at present more than widely recognized (Figure 1).

Figure 1. (a) Dimitri Mendeleev is widely credited with creating (b) the first periodic table of the elements. (credit a: modification of work by Serge Lachinov; credit b: modification of work by "Den fjättrade ankan"/Wikimedia Commons)

By the twentieth century, it became credible that the periodic relationship involved diminutive numbers rather than atomic masses. The modern argument of this relationship, the periodic constabulary, is every bit follows: the properties of the elements are periodic functions of their diminutive numbers. A modern periodic table arranges the elements in increasing lodge of their diminutive numbers and groups atoms with similar backdrop in the same vertical column (Figure 2). Each box represents an element and contains its atomic number, symbol, average atomic mass, and (sometimes) name. The elements are arranged in 7 horizontal rows, called periods or series, and xviii vertical columns, called groups. Groups are labeled at the top of each column. In the The states, the labels traditionally were numerals with majuscule messages. Nonetheless, IUPAC recommends that the numbers 1 through 18 exist used, and these labels are more common. For the table to fit on a single page, parts of two of the rows, a full of 14 columns, are usually written below the primary body of the table.

Figure 2. Elements in the periodic table are organized co-ordinate to their properties.

Many elements differ dramatically in their chemical and physical properties, but some elements are like in their behaviors. For example, many elements appear shiny, are malleable (able to be deformed without breaking) and ductile (can be fatigued into wires), and conduct rut and electricity well. Other elements are not shiny, malleable, or ductile, and are poor conductors of heat and electricity. We can sort the elements into large classes with common properties: metals (elements that are shiny, malleable, good conductors of heat and electricity—shaded yellow); nonmetals (elements that announced dull, poor conductors of rut and electricity—shaded dark-green); and metalloids (elements that acquit estrus and electricity moderately well, and possess some properties of metals and some properties of nonmetals—shaded regal).

The elements tin too be classified into the primary-grouping elements (or representative elements) in the columns labeled 1, 2, and 13–eighteen; the transition metals in the columns labeled iii–12; and inner transition metals in the two rows at the bottom of the table (the top-row elements are chosen lanthanides and the bottom-row elements are actinides; Effigy iii). The elements tin be subdivided further by more specific properties, such as the composition of the compounds they form. For instance, the elements in group ane (the outset column) form compounds that consist of one atom of the element and 1 atom of hydrogen. These elements (except hydrogen) are known as alkali metals, and they all have like chemical properties. The elements in group 2 (the second column) form compounds consisting of one atom of the element and ii atoms of hydrogen: These are chosen alkaline earth metals, with like backdrop among members of that grouping. Other groups with specific names are the pnictogens (grouping fifteen), chalcogens (group 16), halogens (grouping 17), and the noble gases (grouping 18, besides known as inert gases). The groups can besides exist referred to by the first element of the grouping: For example, the chalcogens can be called the oxygen group or oxygen family. Hydrogen is a unique, nonmetallic chemical element with properties like to both group 1A and grouping 7A elements. For that reason, hydrogen may be shown at the summit of both groups, or by itself.

Figure 3. The periodic table organizes elements with like properties into groups.

Click on this link for an interactive periodic table, which you lot can apply to explore the backdrop of the elements (includes podcasts and videos of each element). You may too want to endeavor this one that shows photos of all the elements.

Example 1

Naming Groups of Elements
Atoms of each of the following elements are essential for life. Give the group proper name for the post-obit elements:

(a) chlorine

(b) calcium

(c) sodium

(d) sulfur

Solution
The family names are as follows:

(a) element of group vii

(b) alkaline earth metal

(c) alkali metallic

(d) chalcogen

Check Your Learning
Give the group proper name for each of the post-obit elements:

(a) krypton

(b) selenium

(c) barium

(d) lithium

Answer:

(a) noble gas; (b) chalcogen; (c) alkali metal earth metal; (d) alkali metallic

In studying the periodic table, y'all might have noticed something near the atomic masses of some of the elements. Element 43 (technetium), element 61 (promethium), and almost of the elements with atomic number 84 (polonium) and higher have their atomic mass given in square brackets. This is done for elements that consist entirely of unstable, radioactive isotopes (yous will learn more about radioactivity in the nuclear chemistry chapter). An boilerplate atomic weight cannot be determined for these elements considering their radioisotopes may vary significantly in relative abundance, depending on the source, or may not even exist in nature. The number in foursquare brackets is the atomic mass number (and approximate atomic mass) of the well-nigh stable isotope of that element.

Fundamental Concepts and Summary

The discovery of the periodic recurrence of like properties among the elements led to the formulation of the periodic tabular array, in which the elements are arranged in lodge of increasing atomic number in rows known as periods and columns known equally groups. Elements in the aforementioned group of the periodic tabular array take similar chemical properties. Elements can be classified as metals, metalloids, and nonmetals, or equally a primary-grouping elements, transition metals, and inner transition metals. Groups are numbered 1–xviii from left to right. The elements in grouping 1 are known as the alkali metals; those in group 2 are the element of group i earth metals; those in 15 are the pnictogens; those in sixteen are the chalcogens; those in 17 are the halogens; and those in 18 are the noble gases.

Chemical science Finish of Chapter Exercises

1. Using the periodic tabular array, classify each of the following elements as a metal or a nonmetal, and then further classify each equally a main-group (representative) chemical element, transition element, or inner transition metal:

   (a) uranium

   (b) bromine

   (c) strontium

   (d) neon

   (e) gold

   (f) americium

   (k) rhodium

   (h) sulfur

   (i) carbon

   (j) potassium

2. Using the periodic table, allocate each of the following elements as a metal or a nonmetal, and then further classify each as a master-group (representative) element, transition metal, or inner transition metal:

   (a) cobalt

   (b) europium

   (c) iodine

   (d) indium

   (due east) lithium

   (f) oxygen

   (h) cadmium

   (i) terbium

   (j) rhenium

3. Using the periodic table, identify the lightest fellow member of each of the following groups:

   (a) noble gases

   (b) alkali metal earth metals

   (c) alkali metals

   (d) chalcogens

4. Using the periodic table, identify the heaviest fellow member of each of the following groups:

   (a) alkali metals

   (b) chalcogens

   (c) noble gases

   (d) alkaline earth metals

5. Use the periodic table to requite the name and symbol for each of the following elements:

   (a) the element of group 0 in the same menstruum every bit germanium

   (b) the alkali metal earth metal in the aforementioned period as selenium

   (c) the halogen in the same menses as lithium

   (d) the chalcogen in the aforementioned period every bit cadmium

6. Use the periodic table to give the proper name and symbol for each of the following elements:>

   (a) the halogen in the same period as the alkali metal with eleven protons

   (b) the alkali metal earth metal in the same period with the neutral noble gas with eighteen electrons

   (c) the noble gas in the aforementioned row as an isotope with xxx neutrons and 25 protons

   (d) the noble gas in the same menstruation as gold

7. Write a symbol for each of the post-obit neutral isotopes. Include the atomic number and mass number for each.

   (a) the alkali metal with 11 protons and a mass number of 23

   (b) the noble gas element with 75 neutrons in its nucleus and 54 electrons in the neutral atom

   (c) the isotope with 33 protons and forty neutrons in its nucleus

   (d) the element of group i world metal with 88 electrons and 138 neutrons

8. Write a symbol for each of the post-obit neutral isotopes. Include the diminutive number and mass number for each.

   (a) the chalcogen with a mass number of 125

   (b) the halogen whose longest-lived isotope is radioactive

   (c) the noble gas, used in lighting, with x electrons and 10 neutrons

   (d) the lightest alkali metal with 3 neutrons

Glossary

actinide

inner transition metal in the bottom of the bottom 2 rows of the periodic table

brine metal

element in group 1

alkaline globe metal

chemical element in group 2

chalcogen

element in grouping 16

group

vertical column of the periodic table

halogen

chemical element in group 17

inert gas

(also, noble gas) element in group 18

inner transition metallic

(also, lanthanide or actinide) chemical element in the bottom two rows; if in the first row, also called lanthanide, or if in the second row, also called actinide

lanthanide

inner transition metal in the top of the bottom two rows of the periodic table

chief-group element

(too, representative element) element in columns 1, ii, and 12–18

metal

element that is shiny, malleable, good conductor of heat and electricity

metalloid

element that conducts heat and electricity moderately well, and possesses some properties of metals and some properties of nonmetals

noble gas

(besides, inert gas) chemical element in group xviii

nonmetal

element that appears dull, poor conductor of heat and electricity

menses

(also, series) horizontal row of the periodic table

periodic police force

properties of the elements are periodic function of their atomic numbers.

periodic table

tabular array of the elements that places elements with like chemic properties shut together

pnictogen

element in grouping 15

representative element

(also, main-group element) element in columns ane, 2, and 12–xviii

serial

(also, period) horizontal row of the flow table

transition metal

element in columns 3–11

Solutions

Answers to Chemical science Cease of Chapter Exercises

ane. (a) metal, inner transition metal; (b) nonmetal, representative element; (c) metal, representative chemical element; (d) nonmetal, representative element; (eastward) metal, transition metal; (f) metallic, inner transition metal; (grand) metal, transition metallic; (h) nonmetal, representative element; (i) nonmetal, representative element; (j) metal, representative chemical element

3. (a) He; (b) Be; (c) Li; (d) O

5. (a) krypton, Kr; (b) calcium, Ca; (c) fluorine, F; (d) tellurium, Te

seven. (a) [latex]_{11}^{23}\text{Na}[/latex]; (b) [latex]_{54}^{129}\text{Xe}[/latex]; (c) [latex]_{33}^{73}\text{As}[/latex] ; (d) [latex]_{88}^{226}\text{Ra}[/latex];

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Source: https://iu.pressbooks.pub/openstaxchemistry/chapter/2-5-the-periodic-table/

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