II. Periodic Table

J Deutsch The placement or location of elements on the Periodic Table gives an indication of physical and chemical properties of that element. The elements on the Periodic Table are arranged in order of increasing atomic number. (3.1y) Mendeleev’s original table was according to mass. This was changed when Moseley discovered atomic number.

J Deutsch The number of protons in an atom (atomic number) identifies the element. 6 C The sum of the protons and neutrons in an atom (mass number) identifies an isotope. Common notations that represent isotopes include: 14 C, carbon-14, C-14. (3.1g) Atomic number is written on the bottom left. Mass number is written on the upper left.

J Deutsch Regents Question: 01/03 #9 An atom of carbon-12 and an atom of carbon-14 differ in (1)Atomic number (2)Atomic mass (3)Nuclear charge (4)Number of electrons

J Deutsch Regents Question: 06/02 #4 All the isotopes of a given atom have (1)the same mass number and same atomic number (2)the same mass number but different atomic numbers (3)different mass numbers but the same atomic number (4)different mass numbers and different atomic number

J Deutsch Regents Question: 06/02 #9 Atoms of the same element that have different numbers of neutrons are classified as (1)Charged atoms (2)Charged nuclei (3)Isomers (4)Isotopes

J Deutsch The average atomic mass of an element is the weighted average of the masses of its naturally occurring isotopes. (3.1n) IsotopeMassAbundanceCalculation 12 C %12 x.9889 = C %13 x = Atomic Mass (weighted average) amu

J Deutsch Atomic mass is found on the Periodic Table of the Elements

J Deutsch Regents Question: 01/03 #36 Hydrogen has three isotopes with mass numbers of 1, 2, and 3 and has an average atomic mass of amu. This information indicates that (1)Equal number of each isotope are present (2)More isotopes have an atomic mass of 2 or 3 than 1 (3)More isotopes have an atomic mass of 1 rather than 2 of 3 (4)Isotopes have only an atomic mass of 1

J Deutsch Regents Question: 01/03 #3 In which list are the elements arranged in order of increasing atomic mass? (1)Cl, K, Ar (2)Fe, Co, Ni (3)Te, I Xe (4)Ne, F, Na

J Deutsch Elements can be classified by their properties and located on the Periodic Table as metals, nonmetals, metalloids or semimetals (B, Si, Ge, As, Sb, Te), and noble gases. (3.1v) Metals on the left Nonmetals on the right Metalloids or semimetals

J Deutsch Regents Question: 01/03 # 37 Which list of elements contains two metalloids? (1)Si, Ge, Po, Pb (2)As, Bi, Br, Kr (3)Si, P, S, Cl (4)Po, Sb, I, Xe

J Deutsch Elements can be differentiated by their physical properties. Physical properties of substances, such as density, conductivity, malleability, solubility, and hardness, differ among elements. (3.1w) A physical property is one which does not change the identity of the substance when tested. Density=mass/volume

J Deutsch All elements are solid at room temperature except for the following: Liquids  Mercury (Hg) - the only liquid metal at room temperature  Bromine (Br) - the only liquid nonmetal at room temperature Gases  Hydrogen (H)  Oxygen (O)  Nitrogen (N)  Fluorine (F)  Chlorine (Cl)  All of group 18 (noble gases) Helium (He), Neon (Ne) Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn)

J Deutsch Comparing the physical properties of metals and nonmetals  Silvery gray color except copper and gold  Solid at room temperature except mercury  Good conductors of heat and electricity  Malleable – can be hammered into shapes (thin sheets)  Ductile – can be pulled into wires  Many different colors –Sulfur – yellow –Chlorine – green –Bromine – orange –Iodine - purple  Many different states (phases) –H, N, O – gas –Br – liquid –S, C, I – solid  Poor conductors of heat and electricity (except carbon)  Brittle – breaks when hit Metals Nonmetals

J Deutsch Regents Question: 06/03 # 6 Which is a property of most nonmetallic solids? (1) high thermal conductivity (2) high electrical conductivity (3) brittleness (4) malleability

J Deutsch Elements can be differentiated by chemical properties. Chemical properties describe how an element behaves during a chemical reaction. (3.1x) When testing a chemical property, the substance may change into another substance. The number of atoms an element combines with is an important chemical property: NaClCaCl 2 AlCl 3 CCl 4 HClH 2 ONH 3 CH 4

J Deutsch Some elements exist in two or more forms in the same phase. These forms differ in their molecular or crystal structure, and hence in their properties. (5.2f) These are called allotropes. Allotropes of oxygenAllotropes of carbon Oxygen ( O 2 )Graphite Ozone ( O 3 )Diamond Buckminsterfullerene

J Deutsch For Groups 1, 2, and on the Periodic Table, elements within the same group have the same number of valence electrons (helium is an exception) and therefore similar chemical properties. (3.1z)

J Deutsch Regents Question: 06/03 # Given: Samples of Na, Ar, As, Rb Which two of the given elements have the most similar chemical properties? Explain your answer in terms of the Periodic Table of the Elements. Na and Rb They are in the same group

J Deutsch Group numbers and family names  Group 1Alkali Metals –Very reactive metals, always found as compounds in nature –1 valence electron - lose 1 electron to form +1 ions  Group 2Alkaline Earth Metals –Reactive metals, always found as compounds in nature –2 valence electrons - lose 2 electron to form +2 ions  Group 17Halogens –Reactive nonmetals –7 valence electrons - gain 1 electron to form –1 ions  Groups 18Noble Gases –Not reactive – do not form ions –Filled, stable valence shell (8 electrons except He which has 2)

J Deutsch Regents Question: 01/03 #6 Which Group of the periodic Table contains atoms with a stable outer electron configuration? (1)1 (2)8 (3)16 (4)18

J Deutsch Regents Question: 02/06 #6 Which element is classified as a noble gas at STP? (1)Hydrogen (2)Oxygen (3)Neon (4)Nitrogen STP is standard temperature and pressure 0ºC (273K) and 1 atm (101.3kPa)

J Deutsch The succession of elements within the same group demonstrates characteristic trends: differences in atomic radius, ionic radius, electronegativity, first ionization energy, metallic/nonmetallic properties. (3.1aa) Going down a group, there are more shells separating the nucleus from the valence electrons

J Deutsch The succession of elements across the same period demonstrates characteristic trends: differences in atomic radius, ionic radius, electronegativity, first ionization energy, metallic/nonmetallic properties. (3.1bb) Going across a period, there are more protons pulling on the valence electrons

J Deutsch Reference Table S

J Deutsch Trends in Atomic Radius  Atomic Radius – half the distance between two nuclei  Going down a group, the atomic radius increases because there are more principal energy levels (shells)  Going across a period, the atomic radius decreases because there are more protons pulling the valence shell closer

J Deutsch Atomic Radius

J Deutsch Regents Question: 06/03 #38 Which list of elements is arranged in order of increasing atomic radii? (1)Li, Be, B, C (2) Sr, Ca, Mg, Be (3) Sc, Ti, V, Cr (4) F, Cl, Br, I Check Table S

J Deutsch Forming Ions – making atoms happy  Atoms gain or lose electrons to complete their outer shell –A noble gas configuration –A complete octet –8 electrons  Metals lose electrons to form positive (+) ions  Nonmetals gain electrons to form negative (-) ions  Ionic Radius –A negative ion is always larger than its original atom. –A positive ion is always smaller than its original atom.

J Deutsch Regents Question: 06/03 #37 What is the total number of electrons in a Cu + ion? (1) 28 (2) 29 (3) 30 (4) 36

J Deutsch Ionic Radius in Metals  Sodium (Na) is a metal –Electron configuration (11 protons and 11 electrons) –Loses 1 electron in its valence shell –A sodium atom becomes a sodium ion Na (10 electrons but 11 protons) –Same electron configuration as a noble gas (Ne) but has more protons. Electrons are pulled in much closer so the radius decreases.  2+ ions are even smaller than + ions

J Deutsch Ionic Radius in Nonmetals  Chlorine (Cl) is a nonmetal –Electron configuration (17 protons and 17 electrons) –Gains 1 electron in its valence shell –A chlorine atom becomes a chloride ion Cl (18 electrons but only 17 protons) –Same electron configuration as a noble gas (Ar) but has fewer protons. Electrons repel each other and the radius increases.  2- ions are even larger than – ions Notice-name of negative ions end in IDE

J Deutsch Regents Question: 06/03 #60 As a neutral sulfur atom gains two electrons, what happens to the radius of the atom? It gets bigger

J Deutsch Regents Question: 06/03 #61 After a neutral sulfur atom gains two electrons, what is the resulting charge of the ion? 2-

J Deutsch Regents Question: 08/02 #23 Which electron configuration is correct for a sodium ion? (1) 2–7 (2) 2–8 (3) 2–8–1 (4) 2–8–2

J Deutsch Regents Question: 08/02 #47 Which ion has the same electron configuration as an atom of He? (1) H – (2) O 2– (3) Na + (4) Ca 2+ - means gains 1 electron 2- means gains 2 electrons + means loses 1 electron 2+ means loses 2 electrons GIN LIP Gaining electrons makes Ions Negative Losing electrons makes Ions Positive

J Deutsch Regents Question: 06/02 #39 Which of the following ions has the smallest radius? (1)F - (2)Cl - (3)K + (4)Ca 2+

J Deutsch Regents Question: 06/02 #30 As an atom becomes an ion, its mass number (1)Decreases (2)Increases (3)Remains the sam

J Deutsch Regents Question: 06/02 #10 Compared to the radius of a chlorine atom, the radius of a chloride ion is (1)Larger because chlorine loses an electron (2)Larger because chlorine gains an electron (3)Smaller because chlorine loses an electron (4)Smaller because chlorine gains an electron

J Deutsch Trends in Electronegativity  Electronegativity – the relative ability of an atom to attract electrons (in a chemical bond)  Fluorine (F) has the highest electronegativity and is assigned the value 4.0  Francium (Fr) has the lowest electronegativity.  Going down a group, electronegativity decreases because there are more shells and the electron being attracted is far from the protons  Going across a period, electronegativity increases because there are more protons in the nucleus to attract the electrons. (same number of shells)

J Deutsch Regents Question: 06/02 #11 Which of the following atoms has the greatest tendency to attract electrons? (1)Barium (2)Beryllium (3)Boron (4)Bromine

J Deutsch Regents Question: 01/03 #10 The strength of an atom’s attraction for the electrons in a chemical bond is the atom’s (1)Electronegativity (2)Ionization energy (3)Heat of reaction (4)Heat of formation

J Deutsch Trends in First Ionization Energy  First ionization energy is the amount of energy needed to remove the most loosely held electron from an atom in the gaseous state.  Going down a group, first ionization energy decreases because there are more shells and the electron being attracted is far from the protons  Going across a period, first ionization energy increases because there are more protons in the nucleus to attract the electrons. (same number of shells)

J Deutsch Regents Question: 01/03 #7 From which of these atoms in the ground state can a valence electron be removed using the least amount of energy? (1)Nitrogen (2)Carbon (3)Oxygen (4)Chlorine

J Deutsch Trends in Metallic Properties  Metals want to lose electrons to complete their outer shells  Metals form positive (+) ions  Metals have low electronegativity  Metals have low first ionization energy  Metallic properties (characteristics) decrease as you go to the right across a period  Metallic properties increase as you go down a group  Going towards Francium (Fr), metallic properties increases. Anything that increases an atom’s ability to lose electrons, increase the atoms metallic characteristics.

J Deutsch Trends in Nonmetallic Properties  Nonmetals want to gain electrons to complete their outer shells  Nonmetals form negative (-) ions  Nonmetals have high electronegativity  Nonmetals have high first ionization energy  Nonmetallic properties (characteristics) increase as you go to the right across a period  Nonmetallic properties decrease as you go down a group  Going towards Fluorine (F), nonmetallic properties increases. Anything that increases an atom’s ability to gain electrons, increase the atoms nonmetallic characteristics.

J Deutsch Regents Question: 06/02 #32 Which of the following Group 15 elements has the greatest metallic character? (1)Nitrogen (2)Phosphorous (3)Antimony (4)Bismuth

J Deutsch Regents Question: 06/02 #5 Which are two properties of most nonmetals? (1)High ionization energy and poor electrical conductivity (2)High ionization energy and good electrical conductivity (3)Low ionization energy and poor electrical conductivity (4)Low ionization energy and good electrical conductivity

J Deutsch Regents Question: 06/02 #67-69 On the grid in your answer booklet, set up a scale for electronegativity on the y-axis. Plot the data by drawing the best-fit line. Using the graph, predict the electronegativity of nitrogen For these elements, state the trend in electronegativity in terms of atomic number. ElementAtomic NumberElectronegativity Beryllium41.6 Boron52 Carbon62.6 Fluorine94.0 Lithium31.0 Oxygen83.4

J Deutsch Regents Question: cont’d

J Deutsch Regents Question: cont’d

J Deutsch Regents Question: Cont’d On the grid in your answer booklet, set up a scale for electronegativity on the y-axis. Plot the data by drawing the best-fit line. Using the graph, predict the electronegativity of nitrogen For these elements, state the trend in electronegativity in terms of atomic number. As the atomic number increases, the electronegativity increases