Chemical Bonding: The force that holds two atoms together is called a chemical bond. This bond may be formed many different ways but for now we will only discuss two types of bonds, ionic and covalent. An element’s properties and behavior depends on their valence electrons. These outer electrons are also responsible for how atoms bond to another. Formation of Positive Ions: Groups 1, 2, and 13 will lose electrons to achieve stable octets. This process is favourable because it requires far less energy than gaining multiple electrons. Formation of Negative Ions: Group 15, 16, and 17 have greater attraction to electrons and thus try to gain more electrons to get a stable octet.
Naming with Only One Type of Atom: To name anything with only one type of atom just use the name that appears on the periodic table of elements. However, there are some exceptions to this rule. 1. There are 7 diatomic elements which include H 2, N 2, O 2, F 2, Cl 2, Br 2, and I 2. These elements are found in nature bonded to each other. These still use the names given in the periodic table. Polyatomic Ions: A group of atoms that have a charge. For example, OH - (hydroxide).
2. Monatomic cations use the element name followed by the word ion. Ex. Cs+ is named cesium ion. 3. Monatomic Anions take their name from the root of the element plus the “ide” suffix. Can also be found on your reference sheet. Ex. Br - is named bromide ion. 4. Phosphorous is found in nature in a group of 4 (P 4 ) but is still named phosphorous.
Practice- Name the following Atoms: Li Br 2 Tc Ca 2+ P 4 Rn S 2- Titanium Sodium ion Phosphide ion
When we name elements we name them based on the type of bond they form. Ionic Bonding-ionic bonds are formed between ions with opposite charges. Chemical bonds between metals and non- metals. Covalent Bonding- chemical bonds between non-metals and non-metals. Atoms share electrons.
Ionic Bonds: These bonds are formed when ions are joined due to electrostatic attraction. Typically a metal and a non-metal form ionic bonds. For example, sodium transfers an electron to chlorine gas and forms sodium chloride. If an ionic bond occurs between a metal and oxygen it is an oxide (Fe 2 O 3 ). Most other ionic bonds are salts.
Naming Binary Ionic Compounds (Non- metal and metal): FORMULA 1. Write the symbol of the metal or positive ion first. 2. Write the symbol of the negative ion. Common negative ions and nonmentals are listed on your reference sheet. 3. Overall charge must equal 0. Aluminum chloride is written as AlCl 3 not AlCl.
Al 3+ Mn 4+ Co 3+ Cu 2+ Pb 4+ Cl - O 2- I-I- N 3-
FORMULA TO NAME 1. Write the name of the positive ion followed by the name of the negative ion. Ex. MgO is named magnesium oxide, Na 2 S is named sodium sulfide. NaOH is named sodium hydroxide 2. Common negative ions and nonmentals are listed on your reference sheet. Take these names as they are! DO NOT change them. Ex. Fluorine becomes fluoride and bromine becomes bromide.
3. Many transition metals on the periodic table have more than one possible charge, and therefore when we look at an ionic compound that contains a multivalent metal, we need to be able to identify the charge of the metal ion. If the metal forms more than one type of cation, the charge has to be indicated using roman numerals.
Roman Numerals One (I)Five (V) Two (II)Six (VI) Three (III)Seven (VII) Four (IV)Eight (VIII) Ex. Fe 2+ becomes Fe (II) and Fe 3+ becomes Fe (III). If we have a formula of FeCl 2 which of the following would be the correct name? iron (II) chlorideORiron (III) chloride
Practice – Name the following ionic compounds: NaCl: AlBr 3 : NiO: PdI 4 : PbCl 2 :
Name to Formula 1. Write the name of the cation. Use the roman numerals to predict the charge of each atom. Remember, the Roman numeral is used to help identify the charge of the atoms. 2. Write the name of the anion as shown on your reference sheet. Practice – Write the formula of the following ionic compounds: Sodium oxide: Potassium chloride: Scandium nitride: Cobalt (III) sulfide:
Naming Ionic Bonds with a Polyatomic Ion: Formula to Name: 1. If the polyatomic compound is the cation then use the name found on your reference sheet Ex. Ammonium (NH 4+ ) 2. If the polyatomic compound is the anion find the name on your reference sheet. Use that name and do not change the ending. When using an ion there must be brackets around the entire ion if there is more than one of that ion. Ex. Magnesium cyanate is written as Mg(OCN) 2 NOT as MgOCN 2 Ex. ClO 3 - (chlorate)
3. Again, the charges must equal 0. If they do not you must balance them. Remember, the polyatomic ion is a compound hooked together which means you must use brackets around the term to balance it. Ex. Magnesium nitrate is written as Mg(NO 3 ) 2 Al 3+ H30+H30+ NH 4 + Co 3+ Cu 2+ Pb 4+ SCN - Al(SCN) 3 H 3 OSCNNH 4 SCNCo(SCN) 3 Cu(SCN) 2 Pb(SCN) 4 SO 4 2- Al 2 (SO 4 ) 3 (H 3 O) 2 SO 4 (NH 4 ) 2 SCNCo 2 (SO 4 ) 3 CuSO 4 Pb(SO 4 ) 2 PO 4 2- Al 2 (PO 4 ) 3 (H 3 O) 2 PO 4 (NH 4 ) 2 PO 4 Co 2 (PO 4 ) 3 CuPO 4 Pb(PO 4 ) 2 S 2 O 3 2- Al 2 (S 2 O 3 ) 3 (H 3 O) 2 S 2 O 3 (NH 4 ) 2 S 2 O 3 Co 2 (S 2 O 3 ) 3 CuS 2 O 3 Pb(S 2 O 3 ) 2
Practice – Name the following ionic bonds with polyatomic ions: NaC 2 H 3 O 2 : sodium acetate H 2 O 2 : hydrogen peroxide K 2 HPO 4 : potassium hydrogen phosphate Pt(CrO 4 ) 2 : platinum (IV) chromate Ca(BrO 2 ) 2 : calcium bromite NaOH: sodium hydroxide H 3 OBr: hydronium bromide
Name to Formula: 1. Write the name of the cation. Use the roman numerals to predict the charge of each atom. Remember, the Roman numeral is used to help identify the charge of the atoms. 2. Write the name of the anion as shown on your reference sheet. Remember to include bracket when balancing charges. Practice – Write the formula of the following ionic compounds: Sodium dihydrogen phosphate: Cesium permanganate: Ammonium sulfide: Zinc thiocynate:
Covalent Bonds: The second type of bond is a covalent bond. These bonds occur when both atoms need electrons to get to a stable octet. Instead of transferring electrons they share them. These usually occur with a non-metal and a non- metal. For example, F has an electron configuration of 1s 2 2s 2 2p 5 which means it has 7 valence electrons and must gain one more to achieve a full octet. It achieves this by sharing with another fluorine atom to form F 2. It is important to note that some compounds require more than one covalent bond to achieve an octet, like N 2 or O 2. Because these compounds share electrons NO CHARGES are associated with each atom in the compound.
Naming Covalent Compounds (Non-metal and Non- metal): Formula to Name: 1. The element farthest to the left of the periodic table is named first. If they are in the same column then the one with the most protons is named first. 2. Add the appropriate prefix to the front name (unless the prefix is mono-). This is used to indicate the number of atoms in each compound. Mono- is not used if there is only one atom of the first element. Ex. CO 2 is named carbon dioxide NOT monocarbon dioxide (mono is not used on the first element)
B 3 Br is name triboron monobromide (mono is used on the second one) **Prefixes found on reference sheet. 3. The second uses a prefix and add an “ide” to the ending of the name. Ex. Tetrachloride Practice – Name the following covalent compounds: CO 3 : SF 6 : CO: As 2 O 3 : IF 5 : N 2 O 4 :
Name to Formula: Use the rules above in order to predict the formula: Dichlorine monoxide: Silicon dioxide: Dicarbon trioxide: Carbon monofluoride: Pentanitrogen trioxide: Heptacarbon trinitride: Octaoxygen dinitride:
Formulas with a ● H 2 O These are compounds that have water molecules bonded to them to create a more stable structure. The stable structure may be required to ship the compound from place to place safely. 1. Use the previous rules to name the compound. 2. Attach ● H 2 O (named hydrate) to the end of the compound with the appropriate prefix to indicate the number of water molecules. Ex. NaNO 3 ● 3 H 2 O is named sodium nitrate trihydrate Pb(NO 3 ) 2 ● 5 H 2 O is named lead(II) nitrate pentahydrate
Practice – Name the following compounds containing hydrates: CaCl 2 ● 6H 2 O: Co(NO 3 ) 2 ● 6H 2 O: Cu(NO 3 ) 2 ● 3H 2 O: Practice – Use the same rules to predict the formula: Ammonium sulfide heptahydrate: Iron (II) silicate pentahydrate: Lead (IV) nitrate octahydrate: Copper (II) chloride trihydrate: Gold (III) hydride pentahydrate:
Naming Binary Acids (Hydrogen and 1 Other Element): To name the compound first determine the ending of the root element: Rule #1 –If the anion’s name ends with “-ide”: Add the prefix “hydro –.” Replace the “-ide” ending with “-ic”. Follow the name with the word acid.
Rule #2 –If the anion’s name ends with “-ite”: Replace the “-ite” ending with “-ous”. Follow the name with the word acid. Rule #3 –If the anion’s name ends with “-ate”: Replace the “-ate” ending with “-ic”. Follow the name with the word acid. Ex. HBr is named HIO 3 is named HCrO 3 is named HCl is named HCN is name
Practice – Name the following binary acids: HIO 3 : HF: H 3 PO 3 : H 2 CO 3 : H 2 Cr 2 O 7 : H 2 Se: Give the formula of the following acids: Nitrous acid: Hyrdoselenic acid: hydrosulfuric acid: Chromic acid: Selenous acid:
Hydrocarbons Naming Hydrocarbons: Hydrocarbons are compounds which are composed of hydrogen and carbon units. The majority of hydrocarbons are found in crude oils in which organic matter has decomposed to form these compounds. 1. Alkanes All alkanes have a formula of C n H 2n+2 All alkanes end with 'ane‘ See the prefixes listed on your reference sheet.
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