DOCSLIB.ORG

Discovering a Pattern

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Discovering a Pattern Discovering a Pattern • In 1869, Russian chemist Dmitri Mendeleev arranged the elements in order of increasing atomic mass. •His Periodic table showed that •Elements with similar properties occurred in a repeating pattern •There were gaps in its pattern •He could predict the properties of the missing elements By 1886, all of the gaps had been filled and Mendeleev’s predictions were right. Changing the Arrangement • A few elements’ properties did not fit in the pattern of Mendeleev’s table. • 1914: British scientist Henry Moseley found the atomic number of atoms. • Elements arranged by atomic number fit the pattern in Mendeleev’s table. Elements are arranged: Vertically into Groups Horizontally Into Periods Why? Each group has distinct properties • The periodic Table is divided into several groups based on the properties of different atoms. If you looked at one atom of every element in a group you would see… Each atom has the same number of electrons in it’s outermost shell. • An example… The group 2 atoms all have 2 electrons in their outer shells Be (Beryllium) Atom Mg (Magnesium) Atom Valence electrons • Definition: the number of electrons in the outer shell of an element • Electrons held most loosely • an outer shell is considered complete when it contains 8 electrons • Each element has specific number from 1 to 8 • effects the way an atom bonds • Period ends when valence = 8 • determines many properties of the element • elements within a group usually have similar properties. • One way to represent atoms and molecules is to use electron-dot diagrams. An electron-dot diagram shows only the valence electrons in an atom. If you looked at an atom from each element in a period you would see… Each atom has the same number of electron holding shells. An example… The period 4 atoms each have 4 electron containing shells 4th Shell K (Potassium) Kr (Krypton) Atom Atom Fe (Iron) Atom The Periodic Table and Classes of Elements • Elements are classified as metals, nonmetals, and metalloids based on number of electrons in outer shell •The zigzag line on the periodic table can help you recognize which elements belong in which category. Metals • found to the left of the zigzag line • have few electrons in their outer energy level. • shiny, ductile, malleable, and are good conductors of electric current and thermal energy. Metalloids • border the zigzag line • have about half of a complete set of electrons in their outer energy level. • Metalloids have some properties of metals and some properties of nonmetals. • Metalloids are also called semiconductors. Nonmetals • to the right of the zigzag line • have an almost complete set of electrons in their outer energy level. •not shiny, ductile, or malleable, and poor conductors of electric current and thermal energy. Group 1: Alkali Metals Alkali metals properties: • metals • 1 electron in the outer level • very reactive • softness, color of silver, shininess, low density http://www.lyon. edu/webdata/U Alkali Metals sers/DMcDowel l/GenChem/alka lishow.html Soft, silvery colored metals Very reactive!!! Alkali Metals reacting with water: • Li (Lithium) • Na (Sodium) • K (Potassium) • Rb (Rubidium) • Cs (Cesium) What would you expect from Francium?!?! Group 2: Alkaline-Earth Metals Alkaline-earth metals properties: • metals • 2 electrons in the outer level • very reactive, but less reactive than alkali metals • color of silver, higher densities than alkali metals Alkaline Earth Metals Silvery -White Metals Fairly reactive Many are found in rocks in the earth’s crust Group 3–12: Transition Metals Properties of Transition Metals vary widely but include: • metals • 1 or 2 electrons in the outer level • less reactive than alkaline-earth metals • shininess, good conductors of electric current and thermal energy Transition Metals Most are good Malleable (easily Conductors of bent/hammered into electricity wires or sheets) How many things can you think of that have Transition Metals in them? Metalloids lie on either side of these “stairsteps” They share properties with both metals and non-metals Si (Silicon) and Ge (Germanium) are very important “semi-conductors” What are semiconductors used in? Nonmetals Brittle Do not conduct electricity Group 13: Boron Group Group 13 properties: •one metalloid and five metals • 3 electrons in the outer level • reactive • solids at room temperature Group 14: Carbon Group Group 14 properties: •one nonmetal, two metalloids, and two metals • 4 electrons in the outer level • reactivity varies among the elements • solids at room temperature Group 15: Nitrogen Group Group 15 properties: •two nonmetals, two metalloids, and two metals • 5 electrons in the outer level • reactivity varies among the elements • solids at room temperature (except for nitrogen, which is a gas) Group 16: Oxygen Group Group 16 properties: • group contains three nonmetals, one metalloids, and one metal • 6 electrons in the outer level • reactive • solids at room temperature (except for oxygen, which is a gas) Halogens Most are Poisonous Fairly reactive Chapter 12 Section 2 Grouping the Elements Group 17: Halogens Halogens are the elements in Group 17. Group 17 properties: • group contains nonmetals • 7 electrons in the outer level • very reactive • poor conductors of electric current, never in uncombined form in nature Chlorine Gas was used as a chemical weapon during World War I. It was used by the Nazis in World War II. Chapter 12 Section 2 Grouping the Elements Group 18: Noble Gases Noble gases are the elements in Group 18. Group 18 properties: • group contains nonmetals • 8 electrons in the outer level (except helium, which has 2) • unreactive • colorless, odorless gases at room temperature Noble Gases Unreactive Gases at room temperature Jellyfish lamps made with noble gases artist- Eric Ehlenberger Colors Noble Gases produce in lamp tubes: • Ne (Neon): orange-red • Hg (Mercury): light blue • Ar (Argon): pale lavender • He (Helium): pale peach • Kr (Krypton): pale silver • Xe (Xenon): pale, deep blue Group 3–12: Transition Metals, continued • Lanthanides and Actinides Some transition metals from Periods 6 and 7 appear in two rows at the bottom of the periodic table. Elements in the first row are called lanthanides and elements in the second row are called actinides. Lanthanide Series Actinide Series Hydrogen The properties of hydrogen do not match the properties of any single group, so hydrogen is set apart. • a nonmetal • 1 electron in the outer level • reactive • colorless, odorless gas at room temperature, low density Chapter 11 Section 2 The Atom Isotopes • Isotopes are atoms that have the same number of protons but have different numbers of neutrons. Chapter 11 Section 2 The Atom Isotopes, continued • Properties of Isotopes An unstable atom is an atom with a nucleus that will change over time. This type of isotope is radioactive. • Telling Isotopes Apart You can identify each isotope of an element by its mass number. The mass number is the sum of the protons and neutrons in an atom. Chapter 11 Section 2 The Atom Isotopes, continued • Naming Isotopes: write the name of the element followed by a hyphen and the mass number of the isotope. Example: Uranium-238 •The atomic mass of an element is the weighted average of the masses of all the naturally occurring isotopes of that element. Chapter 11 Section 2 The Atom Chapter 12 The Periodic Tables Concept Map Use the terms below to complete the concept map on the next slide. elements nonmetals periods periodic table metals groups (families) electrons Chapter 12 The Periodic Table Chapter 12 The Periodic Table Chapter 12 Standardized Test Preparation 1. Which of the following statements is correct for the elements shown? A Lithium has the greatest atomic number. B Sodium has the least atomic mass. C Atomic number decreases as you move down the column. D Atomic mass increases as you move down the column. Chapter 12 Standardized Test Preparation 1. Which of the following statements is correct for the elements shown? A Lithium has the greatest atomic number. B Sodium has the least atomic mass. C Atomic number decreases as you move down the column. D Atomic mass increases as you move down the column. Chapter 12 Standardized Test Preparation 2. Which of the following statements best describes the outer electrons in atoms of the elements shown? F The atoms of each element have 1 outer-level electron. G Lithium atoms have 3 outer-level electrons, sodium atoms have 11, and potassium atoms have 19. H Lithium atoms have 7 outer-level electrons, sodium atoms have 23, and potassium atoms have 39. I The atoms of each element have 11 outer-level electrons. Chapter 12 Standardized Test Preparation 2. Which of the following statements best describes the outer electrons in atoms of the elements shown? F The atoms of each element have 1 outer-level electron. G Lithium atoms have 3 outer-level electrons, sodium atoms have 11, and potassium atoms have 19. H Lithium atoms have 7 outer-level electrons, sodium atoms have 23, and potassium atoms have 39. I The atoms of each element have 11 outer-level electrons. Chapter 12 Standardized Test Preparation 3. The elements featured in the image belong to which of the following groups? A noble gases B alkaline-earth metals C halogens D alkali metals Chapter 12 Standardized Test Preparation 3. The elements featured in the image belong to which of the following groups? A noble gases B alkaline-earth metals C halogens D alkali metals Chapter 12 Standardized Test Preparation 2. A chemical company is preparing a shipment of 10 g each of four elements. Each element must be shipped in its own container that is completely filled with the element. Which container will be the largest? F the container of aluminum Density Mass Element (g/cm3) (g) G the container of arsenic Aluminum 2.702 10 H the container of germanium Arsenic 5.727 10 I the container of silicon Germanium 5.350 10 Silicon 2.420 10 Chapter 12 Standardized Test Preparation 2.
Load more

Recommended publications
  • Unit 3 Notes: Periodic Table Notes  John Newlands Proposed an Organization System Based on Increasing Atomic Mass in 1864
    Unit 3 Notes: Periodic Table Notes John Newlands proposed an organization system based on increasing atomic mass in 1864. He noticed that both the chemical and physical properties repeated every 8 elements and called this the ____Law of Octaves ___________. In 1869 both Lothar Meyer and Dmitri Mendeleev showed a connection between atomic mass and an element’s properties. Mendeleev published first, and is given credit for this. He also noticed a periodic pattern when elements were ordered by increasing ___Atomic Mass _______________________________. By arranging elements in order of increasing atomic mass into columns, Mendeleev created the first Periodic Table. This table also predicted the existence and properties of undiscovered elements. After many new elements were discovered, it appeared that a number of elements were out of order based on their _____Properties_________. In 1913 Henry Mosley discovered that each element contains a unique number of ___Protons________________. By rearranging the elements based on _________Atomic Number___, the problems with the Periodic Table were corrected. This new arrangement creates a periodic repetition of both physical and chemical properties known as the ____Periodic Law___. Periods are the ____Rows_____ Groups/Families are the Columns Valence electrons across a period are There are equal numbers of valence in the same energy level electrons in a group. 1 When elements are arranged in order of increasing _Atomic Number_, there is a periodic repetition of their physical and chemical
    [Show full text]
  • The Periodic Table
    THE PERIODIC TABLE Dr Marius K Mutorwa [email protected] COURSE CONTENT 1. History of the atom 2. Sub-atomic Particles protons, electrons and neutrons 3. Atomic number and Mass number 4. Isotopes and Ions 5. Periodic Table Groups and Periods 6. Properties of metals and non-metals 7. Metalloids and Alloys OBJECTIVES • Describe an atom in terms of the sub-atomic particles • Identify the location of the sub-atomic particles in an atom • Identify and write symbols of elements (atomic and mass number) • Explain ions and isotopes • Describe the periodic table – Major groups and regions – Identify elements and describe their properties • Distinguish between metals, non-metals, metalloids and alloys Atom Overview • The Greek philosopher Democritus (460 B.C. – 370 B.C.) was among the first to suggest the existence of atoms (from the Greek word “atomos”) – He believed that atoms were indivisible and indestructible – His ideas did agree with later scientific theory, but did not explain chemical behavior, and was not based on the scientific method – but just philosophy John Dalton(1766-1844) In 1803, he proposed : 1. All matter is composed of atoms. 2. Atoms cannot be created or destroyed. 3. All the atoms of an element are identical. 4. The atoms of different elements are different. 5. When chemical reactions take place, atoms of different elements join together to form compounds. J.J.Thomson (1856-1940) 1. Proposed the first model of the atom. 2. 1897- Thomson discovered the electron (negatively- charged) – cathode rays 3. Thomson suggested that an atom is a positively- charged sphere with electrons embedded in it.
    [Show full text]
  • Metals Metalloids and Nonmetals Properties
    Metals Metalloids And Nonmetals Properties Liveried Elias overrated some cryptanalysts and starve his microbarograph so worriedly! Palpitant or bandy, Spud never ozonizing any sitcoms! Shakable Mic sometimes mobilities any carefulness veer gracefully. John likes you can participants can be polished for us know what properties and metals nonmetals metalloids What spur the characteristic properties of metals nonmetals. Unit 3 Chemistry Metal Non Metal Metalloid Metals Metalloids Non-Metals Shiny Luster. Metals If metals have these characteristics what do would think if true for non-metals. Classifying Metals Non-Metals and Metalloids. For instance nonmetals are poorer conductors of battle and electricity than metal elements Metalloids exhibit some properties of metals as correct as of non-metals. Metals Metalloids and Nonmetals Course Hero. Metals Nonmetals and Metalloids Virginia Department of. Properties of metalloids list Just Hatched. Pin on ScienceDoodads-TPT Products Pinterest. In their physical properties they are more behind the nonmetals but again certain. Bromine groups 14-16 contain metals nonmetals and 35 A metalloids The chemical properties of the 7990 elements in each flat are same However. METALS NONMETALS AND METALLOIDS LESSON PLAN. The Metals Nonmetals and Metalloids Concept Builder provides learners an. Metalloids soil chemistry and prod environment PubMed. Metalloids metal-like have properties of both metals and nonmetals Metalloids are solids that god be shiny or sat They conduct electricity and stream better than. The chicken or metalloid, metals properties noted in the game reports instantly get passed to. Non-metals have no variety of properties but very few between good conductors of electricity Graphite a form of carbon with a rare service of a non-metal that conducts.
    [Show full text]
  • Adsorption Capacity and Removal Efficiency of Heavy Metal Ions By
    chemical engineering research and design 9 0 ( 2 0 1 2 ) 1397–1406 Contents lists available at SciVerse ScienceDirect Chemical Engineering Research and Design j ournal homepage: www.elsevier.com/locate/cherd Adsorption capacity and removal efficiency of heavy metal ions by Moso and Ma bamboo activated carbons a b b,∗ c,d,∗ Sheng-Fong Lo , Song-Yung Wang , Ming-Jer Tsai , Lang-Dong Lin a Department of Forestry and Natural Resources, National Ilan University, I-Lan, Taiwan, ROC b School of Forestry and Resource Conservation, College of Bio-Resource and Agriculture, National Taiwan University, No.1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan, ROC c Department of Cultural Heritage Conservation, National Yunlin University of Science and Technology, Yunlin, Taiwan, ROC d Department of Forest Products Science, National Chiayi University, Chiayi, Taiwan, ROC a b s t r a c t In order to understand the adsorption capacity and removal efficiency of heavy metal ions by Moso and Ma bamboo activated carbons, the carbon yield, specific surface area, micropore area, zeta potential, and the effects of pH value, soaking time and dosage of bamboo activated carbon were investigated in this study. In comparison with once- activated bamboo carbons, lower carbon yields, larger specific surface area and micropore volume were found for the twice-activated bamboo carbons. The optimum pH values for adsorption capacity and removal efficiency of heavy metal ions were 5.81–7.86 and 7.10–9.82 by Moso and Ma bamboo activated carbons, respectively. The optimum 2+ 2+ 2+ 3+ soaking time was 2–4 h for Pb , 4–8 h for Cu and Cd , and 4 h for Cr by Moso bamboo activated carbons, and 1 h for the tested heavy metal ions by Ma bamboo activated carbons.
    [Show full text]
  • Of the Periodic Table
    of the Periodic Table teacher notes Give your students a visual introduction to the families of the periodic table! This product includes eight mini- posters, one for each of the element families on the main group of the periodic table: Alkali Metals, Alkaline Earth Metals, Boron/Aluminum Group (Icosagens), Carbon Group (Crystallogens), Nitrogen Group (Pnictogens), Oxygen Group (Chalcogens), Halogens, and Noble Gases. The mini-posters give overview information about the family as well as a visual of where on the periodic table the family is located and a diagram of an atom of that family highlighting the number of valence electrons. Also included is the student packet, which is broken into the eight families and asks for specific information that students will find on the mini-posters. The students are also directed to color each family with a specific color on the blank graphic organizer at the end of their packet and they go to the fantastic interactive table at www.periodictable.com to learn even more about the elements in each family. Furthermore, there is a section for students to conduct their own research on the element of hydrogen, which does not belong to a family. When I use this activity, I print two of each mini-poster in color (pages 8 through 15 of this file), laminate them, and lay them on a big table. I have students work in partners to read about each family, one at a time, and complete that section of the student packet (pages 16 through 21 of this file). When they finish, they bring the mini-poster back to the table for another group to use.
    [Show full text]
  • January 2019 PRODUCT REGULATORY STATUS Chemical
    January 2019 PRODUCT REGULATORY STATUS Chemical name: carbon black CAS №: 1333-86-4 Product trade name: Carbon black grades: N115, N120, N121, N134, N220, N220FA, N234, N299, N326, N330, N339, N347, N375, N539, N550, N650, N660, N762, N772, N774. Carbon black grades of OMCARB® series: S500, S500A, S500FA, S600FA, S700, S700FA, S800, S810, S820, H80, H100, C40, С50, С60, С70, С80, C140, CH85, СН200, СН210, CH600, P72, P80, P108, P110, P140. Carbon black grades of FairBlack series: R012, R013, R021, R022, R023, R027, R035, R056, R067 HAZARD CLASSIFICATION International Agency for Research on Cancer (IARC) has classified carbon black in Group 2B (may cause cancer in humans). The IARC classification is based on sufficient evidence in animals and inadequate evidence based on human health studies. However, it has been demonstrated with reasonable scientific certainty, that specific mechanism of tumor induction by carbon black in animals (specifically, rats) is not relevant to humans. We continue to believe that carbon black does not present a health hazard when handled in accordance with good housekeeping and safe workplace. See Section 11 of the Safety Data Sheet for additional information. European Union Carbon black is not a hazardous substance under classification criteria of Regulation (EC) 1272/2008 on classification, labelling and packaging of hazardous substances, as well as according to different amendments to this document. Turkey According to the criteria and requirements set forth in the Regulation on classification, labelling and packaging of hazardous substances and mixtures published in the Turkey Official Gazette under No. 28848 on December 11, 2013 (otherwise referred to as SEA Regulation), carbon black is not classified as hazardous substance.
    [Show full text]
  • Investigative Science – ALIEN PERIODIC TABLE Tuesday September 17, 2013 Perry High School Mr
    Investigative Science – ALIEN PERIODIC TABLE Tuesday September 17, 2013 Perry High School Mr. Pomerantz__________________________________________________________________________Page 1 of 2 Procedure: After reading the information below, correctly place the Alien elements in the periodic table based on the physical and chemical properties described. Imagine that scientists have made contact with life on a distant planet. The planet is composed of many of the same elements as are found on Earth. However, the in habitants of the planet have different names and symbols for the elements. The radio transmission gave data on the known chemical and physical properties of the first 30 elements that belong to Groups 1, 2, 13, 14, 15, 16, 17, and 18. SEE if you can place the elements into a blank periodic table based on the information. You may need your Periodic Table as a reference for this activity. Here is the information on the elements. 1. The noble gases are bombal (Bo), wobble, (Wo), jeptum (J) and logon (L). Among these gases, wobble has the greatest atomic mass and bombal has the least. Logon is lighter than jeptum. 2. The most reactive group of metals are xtalt (X), byyou (By), chow (Ch) and quackzil (Q). Of these metals, chow has the lowest atomic mass. Quackzil is in the same period as wobble. 3. The most reactive group of nonmetals are apstrom (A), volcania (V), and kratt (Kt). Volcania is in the same period as quackzil and wobble. 4. The metalloids are Ernst (E), highho (Hi), terriblum (T) and sississ (Ss). Sissis is the metalloid with the highest mass number.
    [Show full text]
  • Is Selenium a Metal, Non-Metal Or Metalloid?
    Is Selenium a metal, non-metal or metalloid? Abstract Is selenium(Se) a metal, non-metal, or a metalloid? There are various public opinions circulating around it. Since a long time from now, there are a lot of voices discussing this. Even until now, there is still no consensus about it. So, in this project, we are trying to find out whether selenium is a non-metal, metal or metalloids base on its physical and chemical properties which could be studied in the secondary school combining with the other information from the internet. Principles and hypothesis Studied from the secondary school chemistry, the general properties of metals include being good conductors of heat and electricity, having high melting and boiling points. Non-metals generally have a lower melting point and boiling point than metals and they being poor conductors of heat and electricity, etc. And the physical properties of metalloids are having extremely high melting/ boiling point, and having fair electrical conductivity. On the other hand, the oxides of metal are generally basic whereas the oxide of non-metals and metalloids are generally acidic. We will define selenium’s chemical category based on the above properties. Besides, we would like to introduce the concept of displacement reaction in studying the chemical properties of the chalcogens(e.g. sulphur(S) and selenium(Se)), especially selenium such rarely mentioned element. We can assume selenium is a metal if selenium could displace a metal oxide or a metal could displace selenium (IV) oxide. If selenium is a non-metal, its oxide could be displaced by sulphur which is supposed to be more reactive than selenium in the chalcogen group.
    [Show full text]
  • Periodic Table of the Elements Notes
    Periodic Table of the Elements Notes Arrangement of the known elements based on atomic number and chemical and physical properties. Divided into three basic categories: Metals (left side of the table) Nonmetals (right side of the table) Metalloids (touching the zig zag line) Basic Organization by: Atomic structure Atomic number Chemical and Physical Properties Uses of the Periodic Table Useful in predicting: chemical behavior of the elements trends properties of the elements Atomic Structure Review: Atoms are made of protons, electrons, and neutrons. Elements are atoms of only one type. Elements are identified by the atomic number (# of protons in nucleus). Energy Levels Review: Electrons are arranged in a region around the nucleus called an electron cloud. Energy levels are located within the cloud. At least 1 energy level and as many as 7 energy levels exist in atoms Energy Levels & Valence Electrons Energy levels hold a specific amount of electrons: 1st level = up to 2 2nd level = up to 8 3rd level = up to 8 (first 18 elements only) The electrons in the outermost level are called valence electrons. Determine reactivity - how elements will react with others to form compounds Outermost level does not usually fill completely with electrons Using the Table to Identify Valence Electrons Elements are grouped into vertical columns because they have similar properties. These are called groups or families. Groups are numbered 1-18. Group numbers can help you determine the number of valence electrons: Group 1 has 1 valence electron. Group 2 has 2 valence electrons. Groups 3–12 are transition metals and have 1 or 2 valence electrons.
    [Show full text]
  • Name Class Period Pre-AP Chemistry: Worksheet # 3.4 Date
    Name Class Period Pre-AP Chemistry: Worksheet # 3.4 Date Directions: Write your answers to the following questions in the space provided. For problem solving, all of the work leading up to the final answer must be shown in order to receive credit. You will not receive credit for “Magic 1. Use the periodic table to separate these 12 elements into six pairs of elements having similar properties. Ca, K, Ga, P, Si, Rb, B, Sr, Sn, Cl, Bi, Br Ca & Sr K & Rb Ga & B P & Bi Si & Sn Cl & Br 2. Use the periodic table to identify by name and symbol the elements that have the following locations. Phosphorus a. Group 15, Period 3 Barium b. Groups 2, Period 6 3. Where are the metals usually found on the periodic table? Where are the nonmetals found? The metalloids? Metals are on the left side and in the center; nonmetals are in the upper-right corner; metalloids form a border between the metals and nonmetals. 4. What are the major differences in the physical properties of metals, nonmetals, and metalloids? Metals—have luster, are malleable and ductile, good conductors of heat and electricity Nonmetals—are dull, not good conductors of heat and electricity, are brittle Metalloids—tend to be brittle, are semiconductors of heat and electricitiy 5. List one distinctive characteristic for the halogens, one for the noble gases, and one for the alkali metals. The halogens are the most reactive nonmetals The noble gases are unreactive. The alkali metals are the most reactive metals. 6. Hydrogen is shown on some periodic tables in two places: both with the alkali metals and with the halogens.
    [Show full text]
  • The Carbon Group Oxidation States Carbon Allotropes of Carbon
    Oxidation States • Properties vary dramatically through this group. Main Group Elements: Group 14 (4A, IV, IVA • Carbon is a nonmetal . The Carbon Group • Carbon is commonly found predominantly in covalent bonds (except carbides). • Silicon, though a semiconductor is mainly nonmetallic. • Germanium is a metalloid or a semi-metal . • At the bottom of the group, tin and lead can be commonly C, Si, Ge, Sn, Pb found in +2 and +4 oxidation states, and commonly found in ionic compounds ( metallic ) 2 2 • Valence electron configuration: ns np +2 ion is stable (seen in lead halides, PbX 2) Lone pair is stereochemically active (participates in determining the molecular geometry) inert pair effect Carbon Allotropes of Carbon - Diamond • Carbon appears in a wide variety of compounds in nature (see: “organic chemistry”), as well as in a large number of • Diamond is one of the hardest known inorganic complexes. substances. It is often used as a • The element is quite abundant in its standard state coating on blades to provide a (graphite ) and exists in a number of other forms ( allotropes harder/sharper surface of diamond and fullerenes are also well known). • It is produced from graphite at very allotropes: different structural forms of the same element high pressures, and is now commonly made synthetically • There are three important isotopes ( 12 C, 13 C, and 14 C). 12 C • 13 Bonding is covalent throughout, with is about 98.9% abundant, while C is about 1.1% 3 abundant. each atom being sp -hybridized. Diamond is thus chemically • 13 C is an important nucleus for NMR (nuclear magnetic unreactive resonance) studies, while 14 C is used for carbon-dating objects ( 14 C has a half-life of about 5730 years) 1 Allotropes of Carbon - Graphite Allotropes of Carbon - Fullerenes • Fullerenes: soccer ball-shaped arrangements of carbon atoms.
    [Show full text]
  • Periodic Table 1 Periodic Table
    Periodic table 1 Periodic table This article is about the table used in chemistry. For other uses, see Periodic table (disambiguation). The periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic numbers (numbers of protons in the nucleus), electron configurations , and recurring chemical properties. Elements are presented in order of increasing atomic number, which is typically listed with the chemical symbol in each box. The standard form of the table consists of a grid of elements laid out in 18 columns and 7 Standard 18-column form of the periodic table. For the color legend, see section Layout, rows, with a double row of elements under the larger table. below that. The table can also be deconstructed into four rectangular blocks: the s-block to the left, the p-block to the right, the d-block in the middle, and the f-block below that. The rows of the table are called periods; the columns are called groups, with some of these having names such as halogens or noble gases. Since, by definition, a periodic table incorporates recurring trends, any such table can be used to derive relationships between the properties of the elements and predict the properties of new, yet to be discovered or synthesized, elements. As a result, a periodic table—whether in the standard form or some other variant—provides a useful framework for analyzing chemical behavior, and such tables are widely used in chemistry and other sciences. Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table.
    [Show full text]