Language of Chemistry Unit 4

Ions If a neutral atom loses electrons, then the atom becomes a positively charged particle. If a neutral atom loses electrons, then the atom becomes a positively charged particle. If a neutral atom gains electrons, then the atom becomes a negatively charged particle. If a neutral atom gains electrons, then the atom becomes a negatively charged particle. An ion is a charged atom. An ion is a charged atom. Metals lose electrons and nonmetals gain Metals lose electrons and nonmetals gain Metals lose 1,2,or3 valence electrons. Metals lose 1,2,or3 valence electrons. Nonmetals gain the valence electrons needed to reach 8 total in the outer shell. Nonmetals gain the valence electrons needed to reach 8 total in the outer shell. The number of electrons an element loses or gains is called the oxidation number. The number of electrons an element loses or gains is called the oxidation number.

ION CHART Val.E Lose/ Gain Los e LoseLoseGainGainGainNeut HowMany IonType + ion - Ion - Ion Neut Oxid.#

Ions A positive ion is called a cation (metals) A positive ion is called a cation (metals) Cations are named by using the element name and the word ion or cation after. Cations are named by using the element name and the word ion or cation after. Mg +2 is the Magnesium ion Mg +2 is the Magnesium ion A negative ion is called an anion (nonmetals) A negative ion is called an anion (nonmetals) Anions are named by using the element root and adding the suffix –ide to the end and also adding the word ion after. Anions are named by using the element root and adding the suffix –ide to the end and also adding the word ion after. F -1 is the fluoride ion F -1 is the fluoride ion

Ion Names Aluminum ion Aluminum ion Oxide ion Oxide ion Hydrogen ion Hydrogen ion Iodide ion Iodide ion Cl -1 Cl -1 Ca +2 Ca +2 N -3 N -3 Li +1 Li +1 P -3 P -3 Al +3 Al +3 O -2 O -2 H +1 H +1 I -1 I -1 Chloride ion Chloride ion Calcium ion Calcium ion Nitride ion Nitride ion Lithium ion Lithium ion Phosphide ion Phosphide ion

Ionic Bonds Forms between a metallic ion and a nonmetallic ion and is called an ionic compound. Forms between a metallic ion and a nonmetallic ion and is called an ionic compound. A chemical compound must have a net charge of zero. So an ionic compound must have equal cations and anions. A chemical compound must have a net charge of zero. So an ionic compound must have equal cations and anions. Na has +1 charge and Cl has –1 charge Na has +1 charge and Cl has –1 charge The compound NaCl is formed with 1 atom of each. The compound NaCl is formed with 1 atom of each.

Ionic Compounds Mg has _______ and Cl has _____ charge. Mg has _______ and Cl has _____ charge. What compound will be formed? What compound will be formed? MgCl 2 : We need two Cl to make a –2 charge to balance out the +2 charge on one Mg atom. MgCl 2 : We need two Cl to make a –2 charge to balance out the +2 charge on one Mg atom. What compounds will form? What compounds will form? Li and P Li and P Al and Se Al and Se Ba and S Ba and S

Naming Ionic Bonds Use the name of the positive ion then the root word of the negative ion with the suffix –ide. Use the name of the positive ion then the root word of the negative ion with the suffix –ide. If it is a transition metal, use the name of the metal with a roman numeral in parenthesis to indicate the oxidation number. If it is a transition metal, use the name of the metal with a roman numeral in parenthesis to indicate the oxidation number. EX: Fe +2 O -2  FeO  Iron (II) Oxide EX: Fe +2 O -2  FeO  Iron (II) Oxide For polyatomics, use the name of the polyatomic even if it is positive or negative. For polyatomics, use the name of the polyatomic even if it is positive or negative.

Practice Naming Ionic Bonds CaS CaS GaBr 3 GaBr 3 Cr 3 N 4 Cr 3 N 4 PbCl 2 PbCl 2 PbO 2 PbO 2 (NH 4 ) 2 Se (NH 4 ) 2 Se Ba(ClO 4 ) 2 Ba(ClO 4 ) 2 Cu(ClO 3 ) 2 Cu(ClO 3 ) 2 Calcium Sulfide Calcium Sulfide Gallium Bromide Gallium Bromide Chromium (IV) Nitride Chromium (IV) Nitride Lead (II) Chloride Lead (II) Chloride Lead (IV) Oxide Lead (IV) Oxide Ammonium Selenide Ammonium Selenide Barium Perchlorate Barium Perchlorate Copper (II) Chlorate Copper (II) Chlorate

Covalent Bonds Occurs between two nonmetals that share their electrons Occurs between two nonmetals that share their electrons TWO TYPES: TWO TYPES: Nonpolar covalent bonds occur between two like nonmetals. H 2 Nonpolar covalent bonds occur between two like nonmetals. H 2 EQUALLY SHARE VALENCE ELECTRONS EQUALLY SHARE VALENCE ELECTRONS 1 SKIP TO 7 MAKE A SEVEN 1 SKIP TO 7 MAKE A SEVEN Polar covalent bonds occur between two different nonmetals in which one atom attracts the electrons more than the other. Polar covalent bonds occur between two different nonmetals in which one atom attracts the electrons more than the other.

Naming covalent bonds Naming covalent bonds Name covalent compounds by using prefixes to indicate how many atoms of each element are in the compound. Name covalent compounds by using prefixes to indicate how many atoms of each element are in the compound. 1. one = _________-5. five = _________- 2. two = _________-6. six = __________- 3. three = ________-7. seven = ________- 4. four = _________-8. eight = _________- Do not use mono- for the first element in the name if there is only one. If there is more than one atom of the first element, then use the prefix needed. Do not use mono- for the first element in the name if there is only one. If there is more than one atom of the first element, then use the prefix needed. Example: CO 2 is _______________________ and C 5 O 6 is_____________________________. Example: CO 2 is _______________________ and C 5 O 6 is_____________________________. MONO DI TRI TETRA PENTA HEXA HEPTA OCTA CARBON DIOXIDE PENTACARBON HEXOXIDE

The Mole A unit used to describe the number of atoms. A unit used to describe the number of atoms x is 1 mole or mol x is 1 mole or mol 1 mol = x atoms 1 mol = x atoms 1 mol = x molecules 1 mol = x molecules 1 mol = x ions 1 mol = x ions

The Mole 1 mol of a substance is equal to the average atomic mass of that element in grams. 1 mol of a substance is equal to the average atomic mass of that element in grams. For example: Carbon weighs amu so 1 mol of C = 12.01g For example: Carbon weighs amu so 1 mol of C = 12.01g Problem: 1 mol of H = 1.008g. If we only have g of H, how many moles do we have? How many atoms of H? Problem: 1 mol of H = 1.008g. If we only have g of H, how many moles do we have? How many atoms of H?

Molar Mass In one molecule of CH 4 (methane), there is one C atom and 4 H atoms. In one molecule of CH 4 (methane), there is one C atom and 4 H atoms. In one mole of CH 4, there is 1 mol of C and 4 mols of H. It is proportional. In one mole of CH 4, there is 1 mol of C and 4 mols of H. It is proportional. If I know the mass of each element, I can find the mass of the whole molecule. If I know the mass of each element, I can find the mass of the whole molecule. Mass of 1 mol of C = 1 x = Mass of 1 mol of C = 1 x = Mass of 4 mol of H = 4 x 1.01 = 4.04 Mass of 4 mol of H = 4 x 1.01 = 4.04 Mass of 1 mol of CH 4 = 16.05g Mass of 1 mol of CH 4 = 16.05g

Mole to Mole ratio In 1 mol of H 2 O, there are 2 mols of H and 1 mol of O. This is a mole to mole ratio. In 1 mol of H 2 O, there are 2 mols of H and 1 mol of O. This is a mole to mole ratio. In 1 mol of Mg 3 (PO 4 ) 2, there are ____ mols of Mg; ______ mols of P; and _____ mols of O. In 1 mol of Mg 3 (PO 4 ) 2, there are ____ mols of Mg; ______ mols of P; and _____ mols of O Problem: Problem: 3.46g H 2 O = ________ g H 3.46g H 2 O = ________ g H Use mole to mole ratio Use mole to mole ratio

Formulas of Compounds Molecular formula – the actual formula of a compound that gives the composition of the molecules that are present. Molecular formula – the actual formula of a compound that gives the composition of the molecules that are present. Empirical Formula – the formula of a compound that expresses the smallest whole- number ratio of the atoms present. Empirical Formula – the formula of a compound that expresses the smallest whole- number ratio of the atoms present. EX. C 6 H 12 O 6 is the __________ formula of sugar EX. C 6 H 12 O 6 is the __________ formula of sugar CH 2 O is the _____________ formula CH 2 O is the _____________ formula

Calculating empirical formulas If we are given the masses of each element present in a compound, we can calculate the original empirical formula. If we are given the masses of each element present in a compound, we can calculate the original empirical formula. Steps for calculating: Steps for calculating: 1. Obtain the mass of each element present in grams. 2. Determine the number of moles of each type of atom present. 3. Divide the number of moles of each element by the smallest number of moles. 1. If all the numbers are whole numbers, they are the subscripts in the formula. 2. If one or more are not whole numbers, go to step Multiply the numbers you found in step 3 by the smallest whole number that will convert all of the numbers to whole numbers. This set will now be the subscripts in the formula.

Practice problem 1. Calculate the empirical formula of g of Aluminum and g of oxygen. Answer = Al 2 O 3 2. Calculate the empirical formula of vanadium oxide if the mass for vanadium is g and the mass of oxygen is g. Answer = V 2 O 5

Percent Composition mass of the element present in 1 mol of compound X 100% mass of the element present in 1 mol of compound X 100% Mass of 1 mol of compound C 2 H 5 OH has a molar mass of ________________ Mass of C = ____________________ Mass of H = ____________________ Mass of O = ____________________ % of each is __________________________________ 46.1 g 2 x 12.0 = 24.0 g 6 x 1.0 = x 16.0 = 16.0g 24.0/46.1 = 52.1%C; 6.0/46.1=13.1%H; 16.0/46.1=34.7%O