CHEMICAL FORMULAS AND CHEMICAL COMPOUNDS

7.1

A compound, whether ionically or covalently bonded, always has the same ratio of moles of atoms. (Law of Definite Proportion)

An ionic compound is composed of ions bonded together. It could be 2 monatomic ions 2 polyatomic ions 1 monatomic and 1 polyatomic

What is the difference between a monatomic and a polyatomic ion?

Monatomic ions contain one atom and polyatomic ions contain 2 or more atoms. The charge for monatomic ions is based on the number of electrons they lose or gain to have a filled valence shell. Some common ones are listed on p. 221.

The charge for monatomic ions is based on the number of electrons they lose or gain to have a filled valence shell. Na Na 1+ Mg Mg 2+ Cl Cl 1- O O 2-

Most transition metals can have more than one charge, but there are two elements in the transition metals that always form the same charged ion. Ag Ag 1+ Zn Zn 2+

Polyatomic ions are groups of atoms that bond covalently, but have an overall charge, so they act as an ion when bonding. Some of the common ones are listed on p. 226.

Oxyanions contain oxygen in varying numbers. ClO 1- is hypochlorite ClO 2 1- is chlorite ClO 3 1- is chlorate ClO 4 1- is perchlorate How do you remember all of these?

Nick the Camel ate Clams for Supper in Phoenix. The underlined letter is the element in the ion. The number of consonants is the number of oxygens. The number of vowels is the charge. The names all end in –ate. NO 3 1- CO 3 2- ClO 3 1- SO 4 2- PO 4 3-

Rules for naming ionic compounds:

1.Cation always comes first If an element forms more than one type of ion, that must be noted using a Roman numeral for the charge. This most often happens in the transition metals.

Rules for naming ionic compounds: 1.Cation always comes first If an element forms more than one type of ion, that must be noted. Cu  Cu 1+ or Cu 2+

Rules for naming ionic compounds: 1.Cation always comes first If an element forms more than one type of ion, that must be noted. Cu  Cu 1+ or Cu 2+ copper (I) copper (II) The common transition metals that we will use are listed on the pink sheet.

Rules for naming ionic compounds: 1.Cation always comes first If an element forms more than one type of ion, that must be noted. 2.Anion always comes second. If it is a monatomic ion (single element) change the ending of the element to –ide.

Rules for naming ionic compounds: 1.Cation always comes first If an element forms more than one type of ion, that must be noted. 2.Anion always comes second. If it is a monatomic ion (single element) change the ending of the element to –ide. If it is a polyatomic ion use the given name.

Rules for writing formulas for ionic compounds: 1.Cation always comes first If a Roman numeral is present, it represents the charge on the cation.

Rules for writing formulas for ionic compounds: 1.Cation always comes first If a Roman numeral is present, it represents the charge on the cation. 2.Anion always comes second.

Rules for writing formulas for ionic compounds: 1.Cation always comes first If a Roman numeral is present, it represents the charge on the cation. 2.Anion always comes second. 3.Balance the charges so that the overall charge is zero.

Rules for writing formulas for ionic compounds: 1.Cation always comes first If a Roman numeral is present, it represents the charge on the cation. 2.Anion always comes second. 3.Balance the charges so that the overall charge is zero. 4.If parentheses are needed to multiply polyatomic ions, use them.

Rules for writing formulas for ionic compounds: 1.Cation always comes first If a Roman numeral is present, it represents the charge on the cation. 2.Anion always comes second. 3.Balance the charges so that the overall charge is zero. 4.If parentheses are needed to multiply polyatomic ions, use them. 5.Check to make sure the lowest ratio of subscripts are used.

ATOMS INVOLVEDCATIONANIONFORMULANAME magnesiumoxygen zincbromine ammoniumsulfur copper (II)fluorine

CATIONANIONFORMULANAME Ca(NO 3 ) 2 FeCl 3 Ag 2 SO 4 (NH 4 ) 3 PO 4

CATIONANIONFORMULANAME magnesium sulfate lead (IV) oxide cobalt (II) hydroxide calcium acetate

IONS QUIZ Worth 50 points Combined with “Ions Cubed” for a lab grade Memorize p. 221 and p. 226 You will have a periodic table without names on it (only symbols) You will not have the pink sheet

Molecular compounds, because they can be bonded more than one way, have different rules.

Molecular compounds, because they can be bonded more than one way have different rules. For instance: CO and CO 2 There are different ways of naming these, and because they are not ions, Roman numerals aren’t used. Although there is a push to use Roman numerals (Stock system) for these as well.

Rules for naming molecular compounds. 1.The element in the lower number group goes first, or if in the same group, the element with the higher period number goes first. This element uses a prefix to denote the number of atoms, but never uses “mono-”. The English name is used.

Rules for naming molecular compounds. 1.The element in the lower number group goes first, or if in the same group, the element with the higher period number goes first. This element uses a prefix to denote the number of atoms, but never uses “mono-”. The English name is used. 2.The second element always uses a prefix also to denote the number of atoms. A root word of the element is used along with the ending “–ide”.

Rules for naming molecular compounds. 1.The element in the lower number group goes first, or if in the same group, the element with the higher period number goes first. This element uses a prefix to denote the number of atoms, but never uses “mono-”. The English name is used. 2.The second element uses a prefix also to denote the number of atoms. A root word of the element is used along with the ending “–ide”. 3.If there are multiple vowels in between the prefix and the root word, one of them is often dropped.

Rules for naming molecular compounds. 1.The element in the lower number group goes first, or if in the same group, the element with the higher period number goes first. This element uses a prefix to denote the number of atoms, but never uses “mono-”. The English name is used. 2.The second element uses a prefix also to denote the number of atoms. A root word of the element is used along with the ending “–ide”. 3.If there are multiple vowels in between the prefix and the root word, one of them is often dropped. 4.When metalloids bond with nonmetals (usually the case), this system of naming is used.

FORMULANAME P4O6P4O6 S 2 Cl 2 AsCl 5 ClF 3 OF 2

FORMULANAME Phosphorous tribromide Nitrogen monoxide Trisulfur nonoxide Iodine pentachloride Tetraarsenic decoxide

Why are acids so unique?

An acid is a covalently bonded molecule which forms ions. HCl + H 2 O  H 3 O 1+ + Cl 1-

Rules for naming acids 1.The anion which forms the basis of the acid is used for the name. 2.If it is a binary acid (hydrogen plus one other element) the name is hydro_________ic acid. 3.If it is an oxygen acid (hydrogen, oxygen plus one other element) the name depends on the number of oxygen atoms present. per__________ic acid (anion is per_____ate) HClO 4 __________ic acid(anion is _____ate) HClO 3 __________ous acid(anion is _____ite) HClO 2 hypo_________ous acid(anion is hypo____ite) HClO

NAMEFORMULAANIONANION NAME Sulfuric acid Perchloric acid Hydrofluric acid

NAMEFORMULAANIONANION NAME HBrO 4 H 2 CO 3 H2SH2S HNO 3

NAMEFORMULAANIONANION NAME Sulfite Nitrite Iodide Acetate