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2.E: Atoms, Molecules, and Ions- Homework

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    For Chapter 2 you MUST know:

    • The names and symbols for elements 1-36
    • Know the polyatomic Ions. You MUST know ammonium (\(\ce{NH4+}\)), acetate ( \(\ce{CH_3COO^-}\)), carbonate ( \(\ce{CO_3^{2-}}\)), hydroxide ( \(\ce{OH^-}\)), nitrate ( \(\ce{NO_3^-}\)), phosphate ( \(\ce{PO_4^{3-}}\)), and sulfate ( \(\ce{SO_4^{2-}}\)).

    Turn in your answers for the following questions - show your work

    1. How many protons, neutrons and electrons are present in one atom of the following:
      1. 1H
      2. 2H
      3. 3H
      4. 79Br
      5. 81Br1-
      6. 262Bh
    2. What is the Atomic Weight of chlorine given that:
      • The exact mass of 35Cl is 34.9689 and the relative abundance is 75.53%
      • The exact mass of 37Cl is 36.9659 and the relative abundance is 24.47%
      • Is this the answer that you expected?
    3. What is the Atomic Weight of ruthenium given the following information from WebElements, www.webelements.com. Is this the answer that you expected?
      • Isotope Abundance Exact Mass
      • 96Ru 5.54% 95.907599
      • 98Ru 1.87% 97.905287
      • 99Ru 12.76% 98.9059389
      • 100Ru 12.60% 99.9042192
      • 101Ru 17.06% 100.9055819
      • 102Ru 31.55% 101.9043485
      • 104Ru 18.62% 103.905424
    4. For the following molecules; write the chemical formula.
      1. carbon dioxide
      2. iron (II) chloride
      3. dinitrogen pentoxide
      4. iron (III) sulfate
    5. Name the following compounds.
      1. KI
      2. CaF2
      3. Cu2SO4
      4. N2O
      5. LiOH
    6. Give the chemical formula (or atomic symbol) and charge for the following ions:
      1. sulfate
      2. sulfite
      3. nitrate
      4. chloride
      5. nitride
      6. acetate
      7. carbonate

    The Following Questions are for your practice - Do Not Turn In.  They include answers so you can check your work

    Atomic Structure and Symbolism

    1. Write the symbol for each of the following ions:
      1. the ion with a 1+ charge, atomic number 55, and mass number 133
      2. the ion with atomic number 15, mass number 31, and a 3− charge
      Answer A
      133Cs+
      Answer B
      31P3−
    2. Give the number of protons, electrons, and neutrons in neutral atoms of each of the following isotopes:
      1. \(\ce{^7_3Li}\)
      2. \(\ce{^{125}_{52}Te}\)
      Answer A
      3 protons, 3 electrons, 4 neutrons
      Answer B
      52 protons, 52 electrons, 73 neutrons

    Chemical Formulas

    1. Write the molecular and empirical formulas of the following compounds:
      1. Figure A shows a carbon atom that forms two, separate double bonds with two oxygen atoms.
      2. >Figure B shows a hydrogen atom which forms a single bond with a carbon atom. The carbon atom forms a triple bond with another carbon atom. The second carbon atom forms a single bond with a hydrogen atom.
      Answer A
      molecular CO2, empirical CO2
      Answer B
      molecular C2H2, empirical CH

    The Periodic Table

    1. Using the periodic table, classify each of the following elements as a metal or a nonmetal, and then further classify each as a main-group (representative) element, transition metal, or inner transition metal:
      1. uranium
      2. bromine
      3. gold
      4. americium
      Answer A
      metal, inner transition metal
      Answer B
      nonmetal, representative element
      Answer C
      metal, transition metal
      Answer D
      metal, inner transition metal

    Molecular and Ionic Compounds

    1. Using the periodic table, predict whether the following chlorides are ionic or covalent: (a) KCl, (b) NCl3, (c) ICl, and (d) PCl5.
      Answer A
      ionic
      Answer B
      covalent
      Answer C
      covalent
      Answer D
      covalent

    Chemical Nomenclature

    1. Name the following compounds:
      1. CsCl
      2. BaO
      3. K2S
      Answer A
      cesium chloride
      Answer B
      barium oxide
      Answer C
      potassium sulfide
    2. Write the formulas of the following compounds:
      1. rubidium bromide
      2. magnesium selenide
      3. calcium chloride
      Answer A
      RbBr
      Answer B
      MgSe
      Answer C
      CaCl2
    3. Write the formulas of the following compounds
      1. chlorine dioxide
      2. dinitrogen tetraoxide
      3. potassium phosphide
      4. silver(I) sulfide
      Answer A
      ClO2
      Answer B
      N2O4
      Answer C
      K3P
      Answer D
      Ag2S
    4. Each of the following compounds contains a metal that can exhibit more than one ionic charge. Name these compounds:
      1. Cr2O3
      2. FeCl2
      3. CrO3
      Answer A
      chromium(III) oxide
      Answer B
      iron(II) chloride
      Answer C
      chromium(VI) oxide

    This page titled 2.E: Atoms, Molecules, and Ions- Homework is shared under a CC BY license and was authored, remixed, and/or curated by Scott Van Bramer.