In General What Do All Elements in the Same Family Have in Common

Chapter two. Atoms, Molecules, and Ions

2.5 The Periodic Tabular array

Learning Objectives

By the terminate of this section, you will be able to:

• State the periodic law and explain the organisation of elements in the periodic table
• Predict the general backdrop of elements based on their location inside the periodic tabular array
• Identify metals, nonmetals, and metalloids past 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 (Grand): These elements all are shiny, behave estrus and electricity well, and have similar chemical backdrop. A second grouping includes calcium (Ca), strontium (Sr), and barium (Ba), which also are shiny, good conductors of heat and electricity, and have chemical properties in common. Still, the specific properties of these two groupings are notably different from each other. For example: Li, Na, and K are much more reactive than are Ca, Sr, and Ba; Li, Na, and K form compounds with oxygen in a ratio of ii of their atoms to i oxygen atom, whereas Ca, Sr, and Ba form compounds with ane of their atoms to one oxygen cantlet. Fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) also exhibit similar properties to each other, but these properties are drastically different from those of whatsoever of the elements above.

Dimitri Mendeleev in Russia (1869) and Lothar Meyer in Germany (1870) independently recognized that there was a periodic relationship among the properties of the elements known at that fourth dimension. Both published tables with the elements arranged co-ordinate to increasing atomic mass. But Mendeleev went one step further than Meyer: He used his table to predict the existence of elements that would have the properties similar to aluminum and silicon, but were yet unknown. The discoveries of gallium (1875) and germanium (1886) provided swell support for Mendeleev's work. Although Mendeleev and Meyer had a long dispute over priority, Mendeleev'south contributions to the development of the periodic table are now more widely recognized (Figure one).

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

By the twentieth century, it became apparent that the periodic relationship involved atomic numbers rather than atomic masses. The modern statement of this relationship, the periodic police force, is as 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 atomic numbers and groups atoms with similar properties in the same vertical cavalcade (Figure ii). Each box represents an element and contains its atomic number, symbol, average atomic mass, and (sometimes) name. The elements are arranged in vii horizontal rows, called periods or series, and 18 vertical columns, called groups. Groups are labeled at the top of each cavalcade. In the Usa, the labels traditionally were numerals with uppercase messages. Nevertheless, IUPAC recommends that the numbers 1 through 18 be 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 fourteen columns, are usually written below the primary torso of the table.

Figure two. Elements in the periodic table are organized according to their properties.

Many elements differ dramatically in their chemical and physical backdrop, but some elements are similar in their behaviors. For case, many elements appear shiny, are malleable (able to be deformed without breaking) and ductile (can be drawn 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 tin sort the elements into large classes with common properties: metals (elements that are shiny, malleable, proficient conductors of heat and electricity—shaded yellow); nonmetals (elements that announced wearisome, poor conductors of heat and electricity—shaded green); and metalloids (elements that conduct heat and electricity moderately well, and possess some backdrop of metals and some backdrop of nonmetals—shaded purple).

The elements tin also exist 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 3–12; and inner transition metals in the two rows at the bottom of the tabular array (the top-row elements are called lanthanides and the bottom-row elements are actinides; Figure 3). The elements can exist subdivided further by more specific properties, such every bit the limerick of the compounds they form. For case, the elements in group i (the outset column) form compounds that consist of ane atom of the chemical element and ane atom of hydrogen. These elements (except hydrogen) are known as brine metals, and they all have similar chemic properties. The elements in grouping 2 (the second cavalcade) form compounds consisting of one atom of the chemical element and two atoms of hydrogen: These are chosen alkaline earth metals, with like properties amid members of that group. Other groups with specific names are the pnictogens (group xv), chalcogens (group 16), halogens (group 17), and the noble gases (group 18, too known as inert gases). The groups can as well be referred to by the showtime element of the grouping: For example, the chalcogens tin can be called the oxygen group or oxygen family. Hydrogen is a unique, nonmetallic element with properties like to both group 1A and grouping 7A elements. For that reason, hydrogen may be shown at the top of both groups, or past itself.

Figure 3. The periodic tabular array organizes elements with similar properties into groups.

Click on this link for an interactive periodic table, which you can use to explore the properties of the elements (includes podcasts and videos of each element). Y'all may besides want to try 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. Requite 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) halogen

(b) alkaline earth metal

(c) brine metal

(d) chalcogen

Cheque Your Learning
Give the grouping name for each of the following elements:

(a) krypton

(b) selenium

(c) barium

(d) lithium

Answer:

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

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

Key Concepts and Summary

The discovery of the periodic recurrence of like backdrop amidst the elements led to the formulation of the periodic table, in which the elements are arranged in order of increasing atomic number in rows known as periods and columns known equally groups. Elements in the same group of the periodic table accept similar chemical properties. Elements tin can exist classified as metals, metalloids, and nonmetals, or every bit a main-group elements, transition metals, and inner transition metals. Groups are numbered 1–eighteen from left to right. The elements in group 1 are known as the brine metals; those in grouping 2 are the alkaline world metals; those in 15 are the pnictogens; those in 16 are the chalcogens; those in 17 are the halogens; and those in 18 are the noble gases.

Chemistry End of Chapter Exercises

1. Using the periodic tabular array, classify each of the following elements equally a metallic or a nonmetal, and then further allocate each every bit a master-grouping (representative) element, transition metal, or inner transition metal:

   (a) uranium

   (b) bromine

   (c) strontium

   (d) neon

   (e) gilded

   (f) americium

   (g) rhodium

   (h) sulfur

   (i) carbon

   (j) potassium

2. Using the periodic tabular array, classify each of the post-obit elements every bit a metal or a nonmetal, and so further classify each every bit a main-grouping (representative) element, transition metal, or inner transition metal:

   (a) cobalt

   (b) europium

   (c) iodine

   (d) indium

   (eastward) lithium

   (f) oxygen

   (h) cadmium

   (i) terbium

   (j) rhenium

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

   (a) noble gases

   (b) alkaline world metals

   (c) brine metals

   (d) chalcogens

4. Using the periodic tabular array, identify the heaviest member of each of the post-obit groups:

   (a) brine metals

   (b) chalcogens

   (c) noble gases

   (d) alkaline metal earth metals

5. Utilise the periodic table to requite the name and symbol for each of the post-obit elements:

   (a) the element of group 0 in the aforementioned period as germanium

   (b) the alkaline earth metal in the same period as selenium

   (c) the element of group vii in the same menstruum equally lithium

   (d) the chalcogen in the same period as cadmium

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

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

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

   (c) the noble gas in the same row as an isotope with 30 neutrons and 25 protons

   (d) the noble gas in the same period as gilt

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 eleven protons and a mass number of 23

   (b) the element of group 0 element with 75 neutrons in its nucleus and 54 electrons in the neutral atom

   (c) the isotope with 33 protons and 40 neutrons in its nucleus

   (d) the alkaline earth metal with 88 electrons and 138 neutrons

8. Write a symbol for each of the following neutral isotopes. Include the atomic 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 10 electrons and 10 neutrons

   (d) the lightest alkaline metal with three neutrons

Glossary

actinide

inner transition metal in the lesser of the lesser two rows of the periodic table

alkaline

element in group 1

alkaline earth metal

element in group 2

chalcogen

element in group 16

group

vertical column of the periodic table

halogen

element in group 17

inert gas

(as well, noble gas) element in group 18

inner transition metal

(besides, lanthanide or actinide) element in the lesser two rows; if in the first row, too called lanthanide, or if in the 2d row, also chosen actinide

lanthanide

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

main-group chemical element

(likewise, representative element) element in columns ane, ii, and 12–18

metal

element that is shiny, malleable, adept 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 law

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

periodic table

table of the elements that places elements with like chemical properties shut together

pnictogen

chemical element in group 15

representative element

(also, master-group element) element in columns 1, 2, and 12–18

serial

(also, period) horizontal row of the period table

transition metal

element in columns 3–xi

Solutions

Answers to Chemistry End of Chapter Exercises

1. (a) metal, inner transition metal; (b) nonmetal, representative element; (c) metallic, representative element; (d) nonmetal, representative element; (e) metallic, transition metal; (f) metal, inner transition element; (g) metal, transition metal; (h) nonmetal, representative element; (i) nonmetal, representative element; (j) metal, representative element

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

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

7. (a) [latex]_{xi}^{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://opentextbc.ca/chemistry/chapter/2-5-the-periodic-table/

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