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

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. ⁸¹Br^1-
   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

2.3: 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

   (a) ¹³³Cs⁺; (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. \(\ce{^{125}_{52}Te}\)
   (a) 3 protons, 3 electrons, 4 neutrons; (b) 52 protons, 52 electrons, 73 neutrons

2.4: Chemical Formulas

Write the molecular and empirical formulas of the following compounds:

(a)

(b)

(a) molecular CO₂, empirical CO₂; (b) molecular C₂H₂, empirical CH

2.5: The Periodic Table

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

(a) metal, inner transition metal; (b) nonmetal, representative element; (c) metal, transition metal; (d) metal, inner transition metal

2.6: Molecular and Ionic Compounds

Using the periodic table, predict whether the following chlorides are ionic or covalent: KCl, NCl₃, ICl, and PCl₅.

Ionic: KCl; Covalent: NCl₃, ICl, PCl₅

2.7: Chemical Nomenclature

Name the following compounds:

1. CsCl
2. BaO
3. K₂S

(a) cesium chloride; (b) barium oxide; (c) potassium sulfide;

Write the formulas of the following compounds:

1. rubidium bromide
2. magnesium selenide
3. calcium chloride

(a) RbBr; (b) MgSe; (c) CaCl₂

Write the formulas of the following compounds:

1. chlorine dioxide
2. dinitrogen tetraoxide
3. potassium phosphide
4. silver(I) sulfide

(a) ClO₂; (b) N₂O₄; (c) K₃P; (d) Ag₂S

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

(a) chromium(III) oxide; (b) iron(II) chloride; (c) chromium(VI) oxide