Which Way Does a Family Run on the Periodic Table

two.5 The Periodic Table

Learning Objectives

Past the end of this section, yous will be able to:

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

As early chemists worked to purify ores and discovered more elements, they realized that various elements could be grouped together by their like chemical behaviors. Ane such grouping includes lithium (Li), sodium (Na), and potassium (Thousand): These elements all are shiny, conduct oestrus and electricity well, and have similar chemical properties. A second grouping includes calcium (Ca), strontium (Sr), and barium (Ba), which too are shiny, good conductors of heat and electricity, and take chemical properties in common. Notwithstanding, the specific backdrop of these two groupings are notably different from each other. For example: Li, Na, and Thousand are much more reactive than are Ca, Sr, and Ba; Li, Na, and K form compounds with oxygen in a ratio of 2 of their atoms to one oxygen atom, whereas Ca, Sr, and Ba form compounds with ane of their atoms to one oxygen atom. Fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) likewise exhibit similar properties to each other, simply these properties are drastically unlike from those of any of the elements above.

Dimitri Mendeleev in Russia (1869) and Lothar Meyer in Germany (1870) independently recognized that there was a periodic relationship amidst the properties of the elements known at that time. Both published tables with the elements bundled according to increasing atomic mass. Just Mendeleev went one step further than Meyer: He used his tabular array 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 cracking back up for Mendeleev's piece of work. Although Mendeleev and Meyer had a long dispute over priority, Mendeleev'south contributions to the development of the periodic table are at present more 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 piece of work past "Den fjättrade ankan"/Wikimedia Commons)

By the twentieth century, it became apparent that the periodic human relationship involved atomic numbers rather than atomic masses. The modern statement of this relationship, the periodic law, is every bit follows: the properties of the elements are periodic functions of their atomic numbers. A modern periodic table arranges the elements in increasing order of their atomic numbers and groups atoms with similar properties in the same vertical column (Figure 2). Each box represents an element and contains its atomic number, symbol, boilerplate atomic mass, and (sometimes) name. The elements are arranged in seven horizontal rows, called periods or serial, and 18 vertical columns, called groups. Groups are labeled at the height of each cavalcade. In the United States, the labels traditionally were numerals with majuscule letters. Yet, 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 total of 14 columns, are usually written beneath the main torso of the table.

Figure 2. Elements in the periodic table are organized according to their backdrop.

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

The elements tin too exist classified into the main-group elements (or representative elements) in the columns labeled 1, ii, and thirteen–18; the transition metals in the columns labeled 3–12; and inner transition metals in the ii rows at the bottom of the table (the top-row elements are called lanthanides and the bottom-row elements are actinides; Figure 3). The elements can exist subdivided farther by more than specific properties, such as the composition of the compounds they grade. For example, the elements in group 1 (the first cavalcade) form compounds that consist of i atom of the element and ane cantlet of hydrogen. These elements (except hydrogen) are known as alkali metals, and they all have similar chemic properties. The elements in group 2 (the second column) form compounds consisting of one atom of the element and two atoms of hydrogen: These are called alkali metal earth metals, with like backdrop among members of that group. Other groups with specific names are the pnictogens (group xv), chalcogens (grouping 16), halogens (group 17), and the noble gases (group 18, also known as inert gases). The groups tin can as well be referred to by the first element of the group: For case, the chalcogens can be called the oxygen grouping or oxygen family unit. 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 table 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 chemical element). You may likewise want to try this one that shows photos of all the elements.

Example 1

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

(a) chlorine

(b) calcium

(c) sodium

(d) sulfur

Solution
The family unit names are equally follows:

(a) element of group vii

(b) element of group ii

(c) alkaline

(d) chalcogen

Check Your Learning
Give the group 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 about the diminutive masses of some of the elements. Element 43 (technetium), element 61 (promethium), and almost of the elements with diminutive number 84 (polonium) and college take their atomic mass given in square brackets. This is done for elements that consist entirely of unstable, radioactive isotopes (you will learn more most radioactive decay in the nuclear chemistry chapter). An average atomic weight cannot be adamant for these elements considering their radioisotopes may vary significantly in relative affluence, depending on the source, or may not even exist in nature. The number in foursquare brackets is the diminutive mass number (and gauge diminutive mass) of the most stable isotope of that chemical element.

Key Concepts and Summary

The discovery of the periodic recurrence of similar properties amid the elements led to the formulation of the periodic table, in which the elements are bundled in social club of increasing atomic number in rows known as periods and columns known as groups. Elements in the same group of the periodic table have similar chemical backdrop. Elements can be classified as metals, metalloids, and nonmetals, or as a main-grouping elements, transition metals, and inner transition metals. Groups are numbered 1–18 from left to right. The elements in group 1 are known as the brine metals; those in grouping 2 are the alkaline 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.

Chemistry End of Affiliate Exercises

1. Using the periodic table, allocate each of the following elements equally a metal or a nonmetal, and then further classify each as a main-grouping (representative) element, transition metallic, or inner transition metal:

   (a) uranium

   (b) bromine

   (c) strontium

   (d) neon

   (e) gold

   (f) americium

   (g) rhodium

   (h) sulfur

   (i) carbon

   (j) potassium

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

   (a) cobalt

   (b) europium

   (c) iodine

   (d) indium

   (e) 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 earth metals

   (c) alkali metals

   (d) chalcogens

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

   (a) brine metals

   (b) chalcogens

   (c) noble gases

   (d) element of group i earth metals

5. Use the periodic tabular array to give the name and symbol for each of the following elements:

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

   (b) the element of group ii in the same period as selenium

   (c) the halogen in the same period equally lithium

   (d) the chalcogen in the aforementioned period as cadmium

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

   (a) the element of group vii in the same catamenia as the alkaline with 11 protons

   (b) the element of group ii in the same period with the neutral noble gas with 18 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 menses equally gold

7. Write a symbol for each of the following 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 alkaline world metallic with 88 electrons and 138 neutrons

8. Write a symbol for each of the following 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 10 electrons and 10 neutrons

   (d) the lightest brine metallic with 3 neutrons

Glossary

actinide

inner transition metal in the bottom of the lesser two rows of the periodic tabular array

alkali metallic

element in group i

alkaline earth metal

element in group 2

chalcogen

element in group 16

group

vertical column of the periodic table

halogen

chemical element in group 17

inert gas

(also, noble gas) element in grouping eighteen

inner transition metal

(likewise, lanthanide or actinide) chemical element in the bottom 2 rows; if in the first row, also called lanthanide, or if in the 2nd row, besides called actinide

lanthanide

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

chief-group element

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

metallic

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

metalloid

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

noble gas

(also, inert gas) chemical element in grouping 18

nonmetal

element that appears tedious, poor conductor of heat and electricity

period

(also, serial) horizontal row of the periodic table

periodic law

backdrop of the elements are periodic role of their diminutive numbers.

periodic table

table of the elements that places elements with like chemic properties close together

pnictogen

element in group 15

representative element

(besides, main-grouping chemical element) element in columns 1, 2, and 12–18

series

(besides, period) horizontal row of the period table

transition metallic

chemical element in columns 3–11

Solutions

Answers to Chemistry End of Affiliate Exercises

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

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

v. (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{Equally}[/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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