Naming Inorganic Compounds UNIT IV Naming Inorganic Compounds

Inorganic Nomenclature nomenclature refers to ‘naming’ The periodic table organizes the elements by vertical groups (________________) and horizontal rows (__________________). The elements are arranged in order of increasing atomic mass; chemical and physical properties form patterns that repeat at regular intervals.

IV.1 The Chemical Elements Element symbol: The first letter is always in upper case and the second letter (if present) is always lower case. 3 Major classifications: Non-Metals Metals Metalloids

IV.2 Naming Inorganic Compounds Ion charges indicate whether atoms of an element want to lose electrons or gain electrons in order to have a full valence shell. METALS: form __________________ions Cation: an ion with a positive charge NON-METALS: form ___________________ ions (H is generally an exception) Anion: an ion with a negative charge

IV.2 Naming Inorganic Compouds Some other definitions: MONATOMIC – DIATOMIC – TRIATOMIC – POLYATOMIC –

IV.2 Naming Inorganic Compounds  1. Naming Monatomic Ions: A. NAMING MONATOMIC METAL IONS use the name of the metal and add the word “ion”. ex: Stock System of naming metal ions: If it is a multivalent metal (more than one charge for the ion), the charge is indicated by roman numerals in brackets.

IV.2 Naming Inorganic Compounds Ex #1: Write the names of the following ions: N3+ = __________________________ Ni2+ = __________________________ Ex #2: Write the formula of the following ions to show their charges: Uranium (VI) ion = __________ Iron (II) ion = __________ Nickel (II) ion = __________

IV.2 Naming Inorganic Compounds B. NAMING MONATOMIC NON-METAL IONS take off the original ending and add an “ide” ending. ex:   Ex #3: Write the names of the following ions: a) Br- = __________________________ b) Cl- = __________________________ c) I- = __________________________ d) O2- = __________________________

IV.2 Naming Inorganic Compounds 2. Naming Polyatomic Ions: What is a polyatomic ion? Rules for naming are more complicated (we won’t learn them). But we will need to KNOW some common polyatomic ions (names, formula, charge). ** Know table on page 69. In order to name compounds, we must know the names and chemical formulae of elements. do self-test on page 66 do question # 1 on page 68

IV.2 Naming Inorganic Compounds 3. How to Write the Formula of an IONIC COMPOUND When Given the Name: An ionic compound = a compound made up of ions. the ions have charges but the compound is a neutral molecule. example: The chemical name of an ionic compound always gives the positive ion (cation) first and the negative ion (anion) second.

IV.2 Naming Inorganic Compounds 3 simple rules: RULE EXAMPLE 1. Write formula for positive ion first, then negative ion.   2. Swap & drop the numbers in front of the charges on the ions (if no number, use a 1). 3. Tidy it up. Reduce subscripts if both can be divided by 2. Omit any subscript that is a 1. Potassium Iodide

IV.2 Naming Inorganic Compounds Ex: Sodium chloride: sodium (Na+), chloride (Cl-)   Ex: Iron (II) sulphate: iron (II) (Fe2+), sulphate (SO42-) Ex: Tin (IV) oxide: tin (IV) (Sn4+), oxide (O2-)  Questions: p. 71 # 4 (odds)

IV.2 Naming Inorganic Compounds 4. How to Write the Chemical Name of an IONIC COMPOUND When Given the Formula: **Check your periodic table to see if the positive ion has more than one ion charge.

IV.2 Naming Inorganic Compounds A) If the first ion has only one possible ion charge: write the names of the ions one after the other omit the word “ion” ex: ZnCl2

IV.2 Naming Inorganic Compounds B) If the first ion has more than one possible charge: “Deswap and dedrop” the charges (find out the charge) check the known charge on negative ion (double or triple charges if needed) write the charge of the positive ion with roman numerals ex: PbO2 ex: Cu2O

IV.2 Naming Inorganic Compounds ** Note: you must memorize the “common name” of 2 compounds: H2O = water NH3 = ammonia Questions: p. 72 #5 (odds)

IV.2 Naming Inorganic Compounds 5. Naming Hydrates Hydrates are ionic compounds that include water molecules in their crystal structures. naming hydrates is pretty straightforward and relies on using prefixes to tell how many water molecules are attached. the # of water molecules is shown after a centered dot

IV.2 Naming Inorganic Compounds **see table of page 72 for prefixes ex: MgSO4·7H2O ex: LiNO3·3H2O Questions: p. 73 #6 and 7

IV.2 Naming Inorganic Compounds 6. Naming COVALENT COMPOUNDS Using the Prefix-Naming System Binary Compound: a compound made of two different types of atoms (usually non-metals) use the prefix-naming system ex: Tertiary Compound: a compound made of three different types of atoms.

IV.2 Naming Inorganic Compounds RULES: each compound name is made of words, each with a suitable prefix see p. 73: first word is the name of element with a prefix to indicate the # of atoms second word is the name of the element with an “ide” ending and a prefix to indicate the # of atoms Exception: if there is only ONE atom of the first element, don’t use the prefix mono. Ex: CO2 =

IV.2 Naming Inorganic Compounds Examples: P2S3 = CO = BrCl3 = S2Cl2 = Questions: p. 74 #8, 9 (odds)

IV.2 Naming Inorganic Compounds 7. Some Common Acids A compound is called an acid when the chemical formula starts with ‘H’ ex: HCl, H2SO4  (see common acids on p. 74 – KNOW THESE)

IV.3 Colours of Some Common Aqueous Ions some ions have characteristics colours. helpful in chemistry to be able to recognize these ions (see table on p. 75 – KNOW) Questions: p. 75 #10-13 Practice Questions Naming - p. 75 # 15 – 65 (odds) Formulas – p. 76 91 – 125 (odds)