Energy: Is the capacity to do work or produce change Energy: Is the capacity to do work or produce change. Potential Energy: Energy available because of the position of an object.

Energy: Is the capacity to do work or produce change Energy: Is the capacity to do work or produce change. Potential Energy: Energy available because of the position of an object. Kinetic Energy: Energy available because of the motion of an object.

Energy: Is the capacity to do work or produce change Energy: Is the capacity to do work or produce change. Potential Energy: Energy available because of the position of an object. Kinetic Energy: Energy available because of the motion of an object. Chemical Energy: The energy stored by compounds.

CHEMICAL SYMBOLS

CHEMICAL SYMBOLS Chemical symbols are shorthand notation for the names of elements. There are 118 known elements. The last several have not been named (in a conventional manner).

If an element has a single letter to represent it – the letter must be capitalized.

If an element has a single letter to represent it – the letter must be capitalized. If an element is represented by two letters – the first letter must be capitalized and the second letter must be lower case. Examples: NO is not the symbol for Nobelium – the correct symbol is No. CO is not the symbol for cobalt – the correct symbol is Co.

CHEMICAL FORMULAS A chemical formula shows the chemical composition of a compound. Three types of chemical formulas will be of interest to us.

CHEMICAL FORMULAS A chemical formula shows the chemical composition of a compound. Three types of chemical formulas will be of interest to us. Molecular formulas

CHEMICAL FORMULAS A chemical formula shows the chemical composition of a compound. Three types of chemical formulas will be of interest to us. Molecular formulas Empirical formulas

CHEMICAL FORMULAS A chemical formula shows the chemical composition of a compound. Three types of chemical formulas will be of interest to us. Molecular formulas Empirical formulas 3. Structural formulas

Molecular formulas An expression showing the exact numbers and types of elements present in a molecule.

Molecular formulas An expression showing the exact numbers and types of elements present in a molecule. Example: The molecular formula for water is H2O – this formula tells us that a molecule of water is formed from 2 atoms of hydrogen (symbol H) 1 atom of oxygen (symbol O) The subscript 2 tells how many atoms of the element on the left of the subscript are present.

When no subscripts are present, the implied number is one When no subscripts are present, the implied number is one. When formulas like (CH3)2CO are encountered, the parenthesis followed by the subscript 2 mean that there are two CH3 groups, so for the given formula, we have: 3 atoms of carbon 6 atoms of hydrogen 1 atom of oxygen

The compound Ni(CO)4 has one atom of Ni, four atoms of carbon, and 4 atoms of oxygen.

Empirical formulas An expression showing types of elements present and the ratio of the different kinds of atoms.

Empirical formulas An expression showing types of elements present and the ratio of the different kinds of atoms. The empirical formula is useful information when the identity of an unknown compound is to be determined.

Empirical formulas An expression showing types of elements present and the ratio of the different kinds of atoms. The empirical formula is useful information when the identity of an unknown compound is to be determined. Note: Many different compounds may have the same empirical formula.

Examples: A molecule of glucose consists of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms – and so its molecular formula is C6H12O6.

Examples: A molecule of glucose consists of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms – and so its molecular formula is C6H12O6. From the formula we see that the proportion of atoms for carbon : hydrogen : oxygen is 6 : 12 : 6 or 1 : 2 : 1 The empirical formula of glucose is CH2O.

For many formulas, the empirical formula is the same as the molecular formula, e.g. H2O.

For many formulas, the empirical formula is the same as the molecular formula, e.g. H2O. Two examples with different molecular formulas but the same empirical formula: Benzene has the molecular formula C6H6 and its empirical formula is CH. Acetylene C2H2, has the empirical formula CH.

For ionic compounds, e.g. sodium chloride, the formula shows the ratio of elements that form the compound.

For ionic compounds, e.g. sodium chloride, the formula shows the ratio of elements that form the compound. Solid sodium chloride consists of a collection of positively charged sodium ions and negatively charged chloride ions in a three-dimensional structure. You cannot say which sodium ion is associated with any particular chloride ion.

For ionic compounds, e.g. sodium chloride, the formula shows the ratio of elements that form the compound. Solid sodium chloride consists of a collection of positively charged sodium ions and negatively charged chloride ions in a three-dimensional structure. You cannot say which sodium ion is associated with any particular chloride ion. The formula NaCl should be regarded as the empirical formula.

STRUCTURAL FORMULAS O water H H An expression showing the exact numbers and types of atoms present in a molecule, and information about how the atoms are chemically bonded to one another. Examples: O water H H

H O O hydrogen peroxide H

H O O hydrogen peroxide H

H H C H methane H

H H ethanol (ethyl alcohol) H C C O H H H

Naming inorganic compounds Two principal groups:

Naming inorganic compounds Two principal groups: (1) metal with nonmetal (or nonmetal group) use Stock system

Naming inorganic compounds Two principal groups: (1) metal with nonmetal (or nonmetal group) use Stock system (2) nonmetal with nonmetal use prefix system

Stock system

Stock system Oxidation number: is the charge that an atom in a compound would have if the electrons in each bond belonged entirely to the more electronegative atom.

Stock system Oxidation number: is the charge that an atom in a compound would have if the electrons in each bond belonged entirely to the more electronegative atom. Electronegativity: relative attraction of an atom for electrons.

Oxidation numbers: In most cases the oxidation number of an element in an ionic compound is the same as the formal charge on the ions present. Example: in the ionic compound KCl, which is composed of K+ ions and Cl- ions, the oxidation number of potassium is +1 and the oxidation number of the chlorine is -1.

For a neutral compound the sum of the oxidation numbers of the elements = 0. Example: for KMnO4 for which the oxidation numbers are K (+1), Mn (+7), and O (-2), the sum of the oxidation numbers = 1 + 7 + 4x(-2) = 0.

For a cation or an anion, the sum of the oxidation numbers of the elements = the charge on the species. Example: For MnO4- the sum of the oxidation numbers = 7 + 4x(-2) = -1, where -1 is the charge on the anion.

The cation is named first.

The cation is named first. The oxidation number is given next (using Roman numerals in parentheses) – if it is needed.

The cation is named first. The oxidation number is given next (using Roman numerals in parentheses) – if it is needed. The oxidation number is given only if the element commonly has more than one oxidation state.

The cation is named first. The oxidation number is given next (using Roman numerals in parentheses) – if it is needed. The oxidation number is given only if the element commonly has more than one oxidation state. The anion is named second.

Examples: FeCl3 Iron forms two common cations, Fe2+ and Fe3+ , hence it will be necessary to specify the oxidation number of the Fe. The name is iron (III) chloride

Examples: FeCl3 Iron forms two common cations, Fe2+ and Fe3+ , hence it will be necessary to specify the oxidation number of the Fe. The name is iron (III) chloride CoPO4 Cobalt forms two common cations, Co2+ and Co3+ , hence it will be necessary to specify the oxidation number of the Co. The name is cobalt (III) phosphate

LiClO3 The cation has only one common oxidation state (which is +1), so it is not necessary to give this as part of the name. The name is lithium chlorate You need to be able to name in both directions: formula name name formula

Give the formula for the following: Iron (II) phosphate The two ions are Fe2+ and PO43- which can be put together Fe2+ PO43- Fe3(PO4)2

calcium sulfate The two ions are Ca2+ and SO42- which can be put together directly as CaSO4 (Note: there are no subscripts of 2 on the calcium and the sulfate ions in the final formula. Keep in mind that we are working with empirical formulas for ionic compounds. The one odd exception to this that you will encounter are the mercury (I) salts.)

To use the Stock system, you need to know the charges on the common cations and anions.

For the anions, pay attention to the endings For the anions, pay attention to the endings. Within a given series, the name of the anion with more oxygen atoms usually ends with an “ate” ending and that with fewer oxygen atoms ends with an “ite” ending. Examples: ClO- hypochlorite ClO2- chlorite ClO3- chlorate ClO4- perchlorate

Prefix system number prefix 1 mon 2 di 3 tri 4 tetra 5 penta 6 hexa 7 hepta 8 octa 9 nona 10 deca Use this for nonmetal nonmetal compounds.

Examples: N2O dinitrogen monoxide (also called dinitrogen oxide)

Examples: N2O dinitrogen monoxide (also called dinitrogen oxide) CO carbon monoxide

Examples: N2O dinitrogen monoxide (also called dinitrogen oxide) CO carbon monoxide Cl2O7 dichlorine heptaoxide

Examples: N2O dinitrogen monoxide (also called dinitrogen oxide) CO carbon monoxide Cl2O7 dichlorine heptaoxide P4O10 tetraphosphorous decaoxide

Examples: N2O dinitrogen monoxide (also called dinitrogen oxide) CO carbon monoxide Cl2O7 dichlorine heptaoxide P4O10 tetraphosphorous decaoxide PF5 phosphorous pentafluoride