Click a hyperlink to view the corresponding slides. Chapter Menu Section 5.1 Ionic Compounds Section 5.2 Covalent Compounds Click a hyperlink to view the corresponding slides. Chapter Menu

Ionic Compounds Apply ionic charge to writing formulas for ionic compounds. Apply formulas to name ionic compounds. Interpret the information in a chemical formula. Section 5.1

Ionic Compounds ion: an atom or group of combined atoms that has a charge because of loss or gain of electrons Section 5.1

Ionic Compounds binary compound formula unit oxidation number polyatomic ion hydrate hygroscopic deliquescent anhydrous The attraction of oppositely charged ions holds atoms in ionic compounds together. Section 5.1

Binary Ionic Compounds Ionic compounds are made up of oppositely charged ions held together strongly in well-organized units. Section 5.1

Binary Ionic Compounds (cont.) A binary compound is a compound that contains only two elements, such as sodium chloride (NaCl). In naming a binary ionic compound, the element with the positively charged ion, usually a metal, is named first with the negatively charged ion, usually a nonmetal, named next, modified to end in –ide. Section 5.1

Binary Ionic Compounds (cont.) For example: oxygen becomes oxide sulfur becomes sulfide fluorine becomes fluoride bromine becomes bromide

Binary Ionic Compounds (cont.) When writing a formula, you add subscripts to the symbols for the ions until the algebraic sum of the ions’ charge is zero. If more than one ion of a given element is present in a compound, the subscript indicates how many ions are present. Section 5.1

Binary Ionic Compounds (cont.) The simplest ratio of ions in a compound is called a formula unit. Section 5.1

Binary Ionic Compounds (cont.) Metals tend to lose electrons and become positively charged. Nonmetals tend to gain electrons and become negatively charged. Section 5.1

Binary Ionic Compounds (cont.) For example: A sodium ion is written as Na1+ meaning it has one positive charge due to the fact that it loses one electron. A chlorine ion is written as Cl1- meaning it has one negative charge due to the fact that it gains one electron. When the charges for these two ions are added together, they equal zero. This means a stable compound can be formed by these two elements.

Binary Ionic Compounds (cont.) The charge on the ion is known as the oxidation number of the atom. Section 5.1

Binary Ionic Compounds (cont.) In a polyatomic ion, an ion that has two or more different elements, a group of elements is covalently bonded together when the atoms share electrons. Section 5.1

Binary Ionic Compounds (cont.) In naming a compound with a polyatomic ion, the molecule with the positive charge is named first, followed by the negative ion. The ending of the negative polyatomic ion name does not change. Section 5.1

Binary Ionic Compounds (cont.) Section 5.1

Compounds of transition elements Transition elements can form more than one type of positive ion and have more than one oxidation number. To distinguish the names of compounds formed from the different ions of a transition element, scientists use a Roman numeral to indicate the oxidation number of a transition element ion. Section 5.1

Compounds of transition elements (cont.) Section 5.1

Compounds of transition elements (cont.) Section 5.1

Hydrates A compound in which there is a specific ratio of water to ionic compound is a hydrate. In a hydrate, the water molecules are chemically bonded to the ionic compound. Section 5.1

Hydrates (cont.) A hygroscopic substance is a substance that absorbs water molecules from the air to become a hydrate. Compounds that form hydrates often are used as drying agents, also called desiccants, because they absorb so much water from the air when they become hydrated. Section 5.1

Hydrates (cont.) Heating hydrates can result in an anhydrous compound, or a compound in which all the water has been removed. To name hydrates, follow the regular name for the compound with the word hydrate, to which a prefix has been added to indicate the number of water molecules present. Section 5.1

Hydrates (cont.) Section 5.1

Interpreting Formulas A formula summarizes how many atoms of each element are present. If more than one formula unit of a compound is present, a coefficient is placed before the formula. Section 5.1

Section Assessment The simplest ratio of ions in a compound is called a(n) ___. A. oxidation unit B. formula unit C. binary compound D. binary ionic compound Section 5.1

Section Assessment Which compound is a binary compound? A. Potassium iodide B. Lithium copper C. Iron magneside D. Sulfur hydrogen Section 5.1

End of Section 5.1

Covalent Compounds Compare the properties of molecular and ionic substances. Distinguish among allotropes of an element. Apply formulas to name molecular compounds. Section 5.2

Covalent Compounds anhydrous: a compound in which all of the water has been removed, usually by heating Section 5.2

Covalent Compounds organic compound distillation inorganic compound molecular element allotrope organic compound inorganic compound hydrocarbon Covalent bonds hold atoms in covalent compounds together. Section 5.2

Properties of Covalent Compounds The properties of most ionic and covalent compounds are different enough that their differences can be used to classify and separate them from one another. Section 5.2

Properties of Covalent Compounds (cont.) Distillation is the method of separating substances in a mixture by the evaporation of a liquid and subsequent condensation of its vapor. Most covalent compounds are not electrolytes because they do not easily form ions. Section 5.2

Molecular Elements A molecule that forms when atoms of the same element bond together is called a molecular element. Section 5.2

Molecular Elements (cont.) Seven nonmetal elements are found naturally as diatomic elements, or molecular elements of two identical atoms. hydrogen nitrogen oxygen fluorine chlorine bromine iodine Section 5.2

Molecular Elements (cont.) Molecules of a single element that differ in crystalline or molecular structure are called allotropes. The properties of allotropes are usually different even though they contain the same element. Section 5.2

Molecular Elements (cont.) Phosphorous has three common allotropes formed from P4 molecules that are joined in different ways. Each allotrope of phosphorous has a unique structure and set of properties. Section 5.2

Molecular Elements (cont.) Carbon occurs as several important allotropes with different properties. Diamonds are crystals in which the atoms of carbon are held rigidly in place in a three-dimensional network. In graphite, carbon atoms are held together closely in flat layers that can slide over each other. Section 5.2

Molecular Elements (cont.) Allotropes of oxygen Ozone consists of three atoms of oxygen, occurs naturally, and is harmful to living things. Section 5.2

Formulas and Names of Covalent Compounds Substances are either organic or inorganic. Compounds that contain carbon, with a few exceptions, are classified as organic compounds. Section 5.2

Formulas and Names of Covalent Compounds (cont.) Compounds that do not contain carbon are called inorganic compounds. If inorganic compounds contain only two nonmetal elements, they are bonded covalently and are referred to as molecular binary compounds. Section 5.2

Formulas and Names of Covalent Compounds (cont.) Naming the compound Name of the first nonmental farthest left on the periodic table is listed first, followed by name of second nonmetal with its ending changed to –ide. Add a prefix to the name of each element to indicate how many atoms of each element are present. Section 5.2

Formulas and Names of Covalent Compounds (cont.) Section 5.2

Formulas and Names of Covalent Compounds (cont.) Some scientists use the more common names for certain compounds, such as water, ammonia, and sulfuric acid. Section 5.2

Formulas and Names of Covalent Compounds (cont.) Section 5.2

Formulas and Names of Covalent Compounds (cont.) The name of even the most complex organic compound is based on the name of a hydrocarbon, an organic compound that contains only the elements hydrogen and carbon. Compounds containing the noble gases helium, neon, and argon have never been found. Section 5.2

Formulas and Names of Covalent Compounds (cont.) Section 5.2

Section Assessment Which of the following is not a hydrocarbon? A. hexane B. nonane C. heptane D. lexane Section 5.2

Section Assessment What is the correct formula for dinitrogen trioxide? A. N2O3 B. N2O2 C. N3O2 D. N2O Section 5.2

Key Concepts The position of an element in the periodic table indicates what charge its ions will have. Binary ionic compounds are named by first naming the metal element and then the nonmetal element, with its ending changed to –ide. Subscripts are used in formulas to indicate how many atoms of each element are present in the compound. Polyatomic ions can combine with ions of opposite charge to form ionic compounds which are named by writing the name of the positive ion first and then the name of the negative ion. Most transition elements can form two or more positively charged ions. The oxidation number of the transition element is indicated by a Roman numeral in parentheses. Hydrates are ionic compounds bonded to water molecules. Study Guide 1

Key Concepts Covalent compounds generally have low melting points, low water solubility, and little or no ability to act as electrolytes. Seven elements occur naturally as diatomic molecules. They are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. Some elements exist in different structural forms called allotropes. Binary covalent compounds are named by writing the two elements in the order they are found in the formula, changing the ending of the second element to –ide, and adding Greek prefixes to the element names to indicate how many atoms of each are present. Study Guide 2

Which compound is not a polyatomic ion? A. sulfate B. potassium chloride C. ammonium D. hydrogen carbonate Chapter Assessment 1

D. hygroscopic substance What kind of substance absorbs water molecules from the air to become a hydrate? A. oxidation compound B. anhydrous compound C. desiccant D. hygroscopic substance Chapter Assessment 2

A formula summarizes how many ___ are present. A. electrons B. atoms C. elements D. compounds Chapter Assessment 3

To create an anhydrous compound, what must be added to the hydrates? A. water B. air C. heat D. light Chapter Assessment 4

What is the method of separating substances in a mixture by the evaporation of a liquid and subsequent condensation of its vapor? A. distillation B. hydration C. oxidation D. molecular division Chapter Assessment 5

How many nonmetal elements are found naturally as molecular elements of two identical atoms? A. six B. seven C. eight D. twelve STP 1

Which of the following is not a diatomic element? A. nitrogen B. bromine C. chlorine D. sulfur STP 2

Which is an allotrope of oxygen? A. graphite B. diamond C. fullerene D. ozone STP 3

Which is the most versatile element in forming allotropes? A. phosphorous B. carbon C. oxygen STP 4

What is the chemical name for water? A. dihydroxide oxygen B. dioxide monohydride C. dihydrogen monoxide D. dioxygen hydroxide STP 5

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