Chemistry 10 Mrs. Howland Rev. Dec 2015

Positively charged ions (Li+) are cations Negatively charged ions (F-) are anions

Polyatomic ions have more than one atom Examples: F - (anion) OH - (polyatomic anion

KNOW THESE! NH 4 + ammoniumNO 3 - nitrate CN - cyanideSO 4 2- sulfate OH - hydoxideCO 3 2- carbonate O 2 2- peroxideClO 3 - chlorate C 2 H 3 O 2 - acetatePO 4 2- phosphate

Why is NaCl called “ Sodium Chloride ” and not “Sodium Chlorine?” Chemistry has its own language Different types of compounds have different types of names Covalent Ionic

1)Identify the CATION: The cation is always written FIRST in the formula for an ionic compound Most cations are monatomic (composed of only 1 atom that has lost electrons to become positively charged) metal ions Some are polyatomic (group of more than 1 atom that has lost electrons to be come positively charged as a unit) You will see Roman numerals associated with some transition metals NaCl cation

2) Identify the ANION: The anion is always written 2 nd in the formula for an ionic compound Trick: cover up the cation  anything left over will be the anion Write the ROOT of the anion with “ide” at the end Some are polyatomic (group of more than 1 atom that has gained electrons to be come negatively charged as a unit) Na Cl anion NAME: Sodium Chloride

__________ are ions with a positive (+) charge. These are written (1 st /2 nd ) in a compound __________ are ions with a negative (-) charge. These are written (1 st /2 nd ) in a compound ____________ ions are one or more elements that act as a group and collectively carry a charge NAME THE FOLLOWING COMPOUND: LiBr

Ions carry a charge Ionic (binary, which means made up of 2) compounds do not have a charge because the charges on the 2 ions (+ for cation and – for anions) cancel each other out Ionic compounds have NO CHARGE! Na + + Cl -  NaCl no charge on NaCl compound because the 1+ and 1- charges cancel each other out

Main-Group Elements (Group A) tend to form IONS that have the same number of valence electrons as its closest noble gas on the Periodic Table Magnesium (Mg) is closest to noble gas Neon, so it loses 2 electrons Mg ion has charge of 2+ Remember! In a chemical reaction and formation of an ionic compound… Cations have positive (+) charge because they LOSE (donate!) electrons Anions have negative charge (-) because they GAIN (accept!) electrons

N/A You don’t have to worry about the Transition metals! (the B groups) The charges written in the YELLOW boxes indicate the CHARGES COMMONLY carried for the elements in those GROUPS. Examples: Na has a charge of 1+ and O has a charge of 2-

You don’t have to worry about the Transition metals! (the B groups)

Remember! “Words” = the chemical name (ex: sodium chloride) “Letters” = the chemical formula (ex: NaCl) Charges must cancel out to make the compound have no charge Use the criss-cross method!

Ionic Compounds Composed of positive (+) and negative (-) ions Usually formed from a metal and non- metal Elements are not attached to one another ~ They are bonded by transfer of electrons which creates electrostatic attraction

The CATION (positive + charge) is always written 1 st and is on the LEFT The ANION (negative – charge) is always written 2 nd and is on the RIGHT Li + O +2- Li is the Lithium ion with the charge 1+ ( the CATION) O Is the Oxygen ion with the charge 2- (the ANION)

“CROSS” the charges to determine the # of each ion present in the ionic compound REMEMBER: Positive (+) and Negative (-) cancel each other out! Li 2 + O +2- Remember a “1” is implied and not written out!

When you have a POLYATOMIC ION, make sure you use PARENTHESES if the subscript is > 1 EXAMPLE: Calcium chlorate Ca + ClO 3 becomes… Ca (ClO 3 ) Remember POLYATOMIC IONS behave as a GROUP

When a ROMAN NUMERAL is shown in a chemical name EXAMPLE: Copper (II) Oxide The element BEFORE the Roman Numeral takes on a positive charge EQUAL to the number EXAMPLE: Copper (II) Oxide becomes… CuO 2 (the 2+ charge on copper gets “crossed” down to Oxygen in the chemical formula)

Q: What is the chemical formula for the ionic compound “lithium oxide?” A: Li 2 O 1)Write out the chemical symbol for the ions or polyatomic ions 2)Find the charge for each of the ions 3)Determine # of each ion needed in order for charges to cancel out 4)“CROSS” the charges to determine the # of each ion present in the ionic compound

Q: What is the chemical formula for the ionic compound “Barium nitride ?” A: Ba 3 N 2 1)Write out the chemical symbol for the ions or polyatomic ions Ba & N 2)Find the charge for each of the ions Ba 2+ & N 3- 3)Determine # of each ion needed in order for charges to cancel out (+2) + (-3) = -1 (do not cancel out  need to do the criss-cross! 4)“CROSS” the charges to determine the # of each ion present in the ionic compound Ba 2+ N 3- Ba 3 N 2

Let’s practice WORKSHEET: NAMING IONIC COMPOUNDS ~ write out the chemical name for each of the chemical compounds

Have COVALENT BONDS Share electrons Usually composed of TWO NONMETALS Elements are attached by bonds

Shows the numbers and kinds of atoms present in a molecule of a compound EXAMPLE: CO (one carbon, one oxygen) MORE EXAMPLES: CS 2 SiO 2 BF 3

Binary means 2 elements Molecular means 2 non-metals NO ionic charges are present PREFIXES are used to show how many atoms are present in each molecule.

CO 2 CARBON DIOXIDE  no ‘mono’ prefix is used on FIRST element  ‘DI’ means there are TWO oxygens!! HOW TO NAME: FIRST element: just the name! SECOND ELEMENT: (prefix + element root + ide) i.e.PCl 3 Phosphorous Trichloride All binary compounds end in ide!!!

When the addition of a prefix makes TWO A’s or TWO O’s next to each other, drop the first vowel EXAMPLE: NONAOXIDE becomes NONOXIDE (drop the A) EXAMPLE: MONOOXIDE becomes MONOXIDE (drop the first O) BUT the “I” at the end of ‘DI’ and ‘TRI’ are NEVER dropped!!

NAME THE FOLLOWING: CCl 4

When the ANION ends in ‘ide’ Example: HCl becomes Hydrochloric Acid Acid Name: (root)- icacid When the ANION ends in ‘ite’ Example: Hydrogen Sulfite becomes Sulfurous Acid Acid Name: (stem)-ous acid When the ANION ends in ‘ate’ Example: Hydrogen sulfate becomes Sulfuric Acid Acid name: (stem)-ic acid