Skip to content Skip to sidebar Skip to footer
الصفحة الرئيسية / Why Are Columns on the Periodic Table Called Families

Why Are Columns on the Periodic Table Called Families

إرسال تعليق

Learning Outcomes

  • State the periodic police and explicate the organization of elements in the periodic table
  • Predict the general properties of elements based on their location within the periodic table
  • Identify metals, nonmetals, and metalloids by 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. One such grouping includes lithium (Li), sodium (Na), and potassium (K): These elements all are shiny, acquit rut and electricity well, and have like chemic properties. A 2nd grouping includes calcium (Ca), strontium (Sr), and barium (Ba), which also are shiny, good conductors of heat and electricity, and accept chemical properties in common. However, the specific properties of these two groupings are notably dissimilar from each other. For case: Li, Na, and K are much more reactive than are Ca, Sr, and Ba; Li, Na, and K course compounds with oxygen in a ratio of two of their atoms to one oxygen atom, whereas Ca, Sr, and Ba form compounds with one of their atoms to 1 oxygen cantlet. Fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) also exhibit like properties to each other, but these properties are drastically unlike from those of any of the elements to a higher place.

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

Figure A shows a photograph of Dimitri Mendeleev. Figure B shows the first periodic table developed by Mendeleev, which had eight groups and twelve periods. In the first group (—, R superscript plus sign 0) is the following information: H = 1, L i = 7, N a = 23, K = 39, (C u = 63), R b = 85, (A g = 108), C a = 183, (—),—, (A u = 199) —. Note that each of these entries corresponds to one of the twelve periods respectively. The second group (—, R 0) contains the following information: (not entry for period 1) B o = 9, 4, M g = 24, C a = 40, Z n = 65, S r = 87, C d = 112, B a = 187, —, —, H g = 200, —. Note the ach of these entries corresponds to one of the twelve periods respectively. Group three (—, R superscript one 0 superscript nine) contains the information: (no entry for period 1), B = 11, A l = 27, 8. — = 44, — = 68, ? Y t = 88, I n = 113, ? D I = 138, —, ? E r = 178, T l = 204, —. Note that each of these entries corresponds to one of the twelve periods respectively. Group four (RH superscript four, R0 superscript eight) contains the following information: (no entry for period 1), C = 12, B i = 28, T i = 48, — = 72, Z r = 90, S n = 118, ? C o = 140, ? L a = 180, P b = 207, T h = 231. Note that each of these entries corresponds to one of the twelve periods respectively. Group five (R H superscript two, R superscript two 0 superscript five) contains the following information: (no entry for period 1), N = 14, P = 31, V = 51, A s = 75, N b = 94, S b = 122, —, —, T a = 182, B l = 208, —. Note that each of these entries corresponds to one of the twelve periods respectively. Group six (R H superscript two, R 0 superscript three) contains the following information: (no entry for period 1), O = 16, S = 32, C r = 52, S o = 78, M o = 96, T o = 125, —, —, W = 184, —, U = 240. Note that each of these entries corresponds to one of the twelve periods respectively. Group seven (R H , R superscript plus sing, 0 superscript 7) contains the following information: (no entry for period 1), F = 19, C l = 35, 5, M n = 55, B r = 80, — = 100, J = 127, —, —, —, —, —. Note that each of these entries corresponds to one of the twelve periods respectively. Group 8 (—, R 0 superscript four) contains the following information: (no entry for periods 1, 2, 3), in period 4: F o = 56, C o = 59, N i = 59, C u = 63, no entry for period five, in period 6: R u = 104, R h = 104, P d = 106, A g = 108, no entries for periods 7, 8 , or 9, in period 10: O s = 195, I r = 197, P t = 198, A u = 199, no entries for periods 11 or 12.

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

Y'all can view the transcript for "The Periodic Table: Crash Form Chemistry #four" here (opens in new window).

By the twentieth century, information technology became apparent that the periodic human relationship involved atomic numbers rather than atomic masses. The modern statement of this relationship, the periodic police, is equally follows: the properties of the elements are periodic functions of their diminutive numbers. A modern periodic table arranges the elements in increasing order of their atomic numbers and groups atoms with similar backdrop in the same vertical column (Figure 2). Each box represents an chemical element and contains its atomic number, symbol, average atomic mass, and (sometimes) name. The elements are arranged in seven horizontal rows, chosen periods or series, and 18 vertical columns, chosen groups. Groups are labeled at the tiptop of each column. In the United States, the labels traditionally were Roman numerals with capital letters. Withal, IUPAC recommends that the numbers i through eighteen be used, and these labels are more common. For the tabular array to fit on a single page, parts of two of the rows, a total of 14 columns, are usually written below the main torso of the table.

The Periodic Table of Elements is shown. The 18 columns are labeled

Effigy two. Elements in the periodic tabular array are organized according to their properties.

Many elements differ dramatically in their chemic 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 oestrus and electricity well. Other elements are non shiny, malleable, or ductile, and are poor conductors of heat and electricity. We can sort the elements into large classes with mutual backdrop: metals (elements that are shiny, malleable, practiced conductors of heat and electricity—shaded yellow); nonmetals (elements that announced dull, poor conductors of rut and electricity—shaded green); and metalloids (elements that deport oestrus and electricity moderately well, and possess some properties of metals and some properties of nonmetals—shaded purple).

The elements can besides exist classified into the main-grouping elements (or representative elements) in the columns labeled 1, two, and 13–18; the transition metals in the columns labeled 3–12; and inner transition metals in the ii rows at the lesser of the table (the top-row elements are called lanthanides and the bottom-row elements are actinides; Effigy 3). The elements can exist subdivided further by more specific properties, such every bit the composition of the compounds they grade. For case, the elements in group 1 (the first cavalcade) grade compounds that consist of one atom of the element and one cantlet of hydrogen. These elements (except hydrogen) are known as alkali metals, and they all have similar chemical properties. The elements in group ii (the second cavalcade) form compounds consisting of one atom of the element and ii atoms of hydrogen: These are called alkaline earth metals, with like backdrop among members of that group. Other groups with specific names are the pnictogens (group 15), chalcogens (group 16), halogens (grouping 17), and the noble gases (group xviii, also known as inert gases). The groups tin can as well exist referred to by the first element of the group: For example, the chalcogens tin exist called the oxygen group or oxygen family. Hydrogen is a unique, nonmetallic chemical element with properties similar to both group 1 and group 17 elements. For that reason, hydrogen may exist shown at the top of both groups, or past itself.

This diagram combines the groups and periods of the periodic table based on their similar properties. Group 1 contains the alkali metals, group 2 contains the earth alkaline metals, group 15 contains the pnictogens, group 16 contains the chalcogens, group 17 contains the halogens and group 18 contains the noble gases. The main group elements consist of groups 1, 2, and 12 through 18. Therefore, most of the transition metals, which are contained in groups 3 through 11, are not main group elements. The lanthanides and actinides are called out at the bottom of the periodic table.

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

Click on this link to the Royal Society of Chemistry for an interactive periodic table, which you can employ to explore the properties of the elements (includes podcasts and videos of each element). You may besides want to attempt this one from PeriodicTable.com 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 name for the post-obit elements:

  1. chlorine
  2. calcium
  3. sodium
  4. sulfur

Check Your Learning

Requite the group proper noun for each of the following elements:

  1. krypton
  2. selenium
  3. barium
  4. lithium

In studying the periodic table, yous might take noticed something about the atomic masses of some of the elements. Chemical element 43 (technetium), element 61 (promethium), and virtually of the elements with diminutive 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 (you will learn more most radioactivity in the nuclear chemical science module). An average atomic weight cannot be determined for these elements considering their radioisotopes may vary significantly in relative abundance, depending on the source, or may not fifty-fifty exist in nature. The number in square brackets is the diminutive mass number (and approximate atomic mass) of the most stable isotope of that chemical element.

Key Concepts and Summary

The discovery of the periodic recurrence of similar properties amidst the elements led to the formulation of the periodic table, in which the elements are arranged in society of increasing atomic number in rows known as periods and columns known as groups. Elements in the aforementioned group of the periodic table have like chemical properties. Elements tin be classified as metals, metalloids, and nonmetals, or equally a main-grouping 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 alkali metals; those in group 2 are the alkaline globe 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.

Effort It

Metal or Nonmetal?

  1. Using the periodic table, classify each of the post-obit elements every bit a metal or a nonmetal, and so further classify each as a master-group (representative) chemical element, transition metallic, or inner transition metal:
    1. uranium
    2. bromine
    3. strontium
    4. neon
    5. gilt
    6. americium
    7. rhodium
    8. sulfur
    9. carbon
    10. potassium
  2. Using the periodic table, allocate each of the post-obit elements as a metallic or a nonmetal, and and then further classify each as a chief-group (representative) chemical element, transition element, or inner transition metal:
    1. cobalt
    2. europium
    3. iodine
    4. indium
    5. lithium
    6. oxygen
    7. cadmium
    8. terbium
    9. rhenium

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

Identifying Elements

  1. Using the periodic table, identify the lightest member of each of the following groups:
    1. noble gases
    2. alkaline earth metals
    3. alkali metals
    4. chalcogens
  2. Using the periodic table, identify the heaviest member of each of the following groups:
    1. brine metals
    2. chalcogens
    3. noble gases
    4. alkaline metal globe metals
  3. Use the periodic table to give the name and symbol for each of the following elements:
    1. the noble gas in the same period equally germanium
    2. the alkaline metal globe metal in the same period every bit selenium
    3. the halogen in the same menses as lithium
    4. the chalcogen in the same period as cadmium
  4. Use the periodic table to give the name and symbol for each of the following elements:
    1. the halogen in the aforementioned period as the alkali metal with xi protons
    2. the element of group i world metallic in the same flow with the neutral noble gas with 18 electrons
    3. the element of group 0 in the same row as an isotope with 30 neutrons and 25 protons
    4. the noble gas in the aforementioned menstruum as gold
  5. Write a symbol for each of the following neutral isotopes. Include the diminutive number and mass number for each.
    1. the alkali metallic with 11 protons and a mass number of 23
    2. the noble gas element with and 75 neutrons in its nucleus and 54 electrons in the neutral atom
    3. the isotope with 33 protons and 40 neutrons in its nucleus
    4. the element of group ii with 88 electrons and 138 neutrons
  6. Write a symbol for each of the following neutral isotopes. Include the atomic number and mass number for each.
    1. the chalcogen with a mass number of 125
    2. the halogen whose longest-lived isotope is radioactive
    3. the noble gas, used in lighting, with 10 electrons and ten neutrons
    4. the lightest alkaline with three neutrons

Glossary

actinide:inner transition metal in the lesser of the bottom 2 rows of the periodic table

alkali metal:chemical element in group 1

alkaline earth metal:chemical element in group 2

chalcogen:element in grouping 16

group:vertical column of the periodic table

halogen:element in group 17

inert gas:(also, noble gas) element in group 18

inner transition metal:(also, lanthanide or actinide) element in the bottom two rows; if in the beginning row, besides called lanthanide, of if in the second row, as well called actinide

lanthanide:inner transition metal in the pinnacle of the lesser two rows of the periodic table

chief-grouping element:(likewise, representative element) element in columns 1, 2, and 12–18

metal:element that is shiny, malleable, good conductor of rut and electricity

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

noble gas:(too, inert gas) element in group xviii

nonmetal:element that appears deadening, poor conductor of heat and electricity

menses:(also, series) horizontal row of the catamenia table

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

periodic table:table of the elements that places elements with similar chemical backdrop close together

pnictogen:element in grouping 15

representative chemical element:(besides, main-group element) element in columns 1, 2, and 12–eighteen

serial:(as well, period) horizontal row of the flow table

transition metal:element in columns 3–11

ashobabounceept.blogspot.com

Source: https://courses.lumenlearning.com/chemistryformajors/chapter/the-periodic-table-4/

إرسال تعليق for "Why Are Columns on the Periodic Table Called Families"