Writing Chemical Formulas & Naming Compounds

STUFF noun st. f (1) The material(s) of which things are made (2) A word never to be used from this day forth in chemistry class when referring to the material(s) of which things are made….

The elements in the Periodic Table are arranged according to similarities in their properties…

Metals: 1.Generally hard and shiny 2.Conduct heat and electricity well. 3.Malleable and ductile 4.Few valence electrons 5.Tend to lose valence electronsNonmetals 1.Generally gases or brittle solids at room temperature 2.More valence electrons 3.Tend to gain valence electrons

Metalloids Exhibit properties of both metals and nonmetals Are used in making semiconductors Semiconductors conduct electricity by using a free electron that is available with impurities are introduced into the crystal. Semiconductors are used in transistors & solar cells

Predicting Chemical Formulas Ionic Substances: When metals combine with nonmetals an ionic substance results. It is often fairly easy to predict the chemical formulas of ionic substance by determining the ions that are formed.

Forming Ions When metals LOSE electrons they become cations When nonmetals GAIN electrons they become anions Be +2 4 protons… +4 2 electrons.. -2 Net charge…. +2 N -3 7 protons… electrons Net charge…. -3

Oxidation Numbers When atoms react and form ions…. It is possible to predict the charge on the ion formed. MONATOMIC ION When a single atom takes on a charge it is called a MONATOMIC ION. OXIDATION NUMBER The charge on the monatomic ion is known as the OXIDATION NUMBER.

Question: What does an oxidation number of 0 mean?

Common Metal Ions with More than One Oxidation Number FormulaStock NameClassical Name Cu +1 Copper (I) ionCuprous ion Cu +2 Copper (II) ionCupric ion Fe +2 Iron (II) ionFerrous ion Fe +3 Iron (III) ionFerric ion Pb +2 Lead (II) ionPlumbous ion Pb +4 Lead (IV) ionPlumbic ion Sn +2 Tin (II) ionStannous ion Sn +4 Tin (IV) ionStannic ion

Binary Compounds: Compounds composed of only 2 elements. For example combine Calcium and Bromine Calcium ion is Ca +2 Bromine ion is Br -1 If combine Ca:Br as 1:1 then charge is NOT balanced……..…... +2:-1 If combine Ca:Br as 1:2 then charge is balanced…. 1(+2):2(-1) +2:-2

Criss-Cross Compounds… A shortcut to figuring the necessary ratio between two ions is the criss-cross method. Note: After Criss-Cross reduce to lowest whole number ratio…

Practice with Binary Ionic Compounds Combine the following elements: 1)Calcium and Sulfur 2)Magnesium and Nitrogen 3) Tin(IV) and Oxygen

Naming Binary Ionic Compounds Name cation followed by anion Give anion an “ide” ending Uncriss-cross to find out the correct cation name

Practice with Naming Binary Ionic Compounds Name the following binary compounds: 1)AlI 3 2)FeO 3) CaSe

Polyatomic Ions Groups of atoms of more than one element that carry a charge Bound tightly and do not ordinarily break during chemical reactions Behave as though they were single atoms

Ternary Ionic Compounds contain more than 2 elements. Same procedure as binary compounds except the endings of the polyatomic ions have different endings.

Practice with Ternary Ionic Compounds Write the formulas for these compounds: 1)Magnesium Hydroxide 2)Barium Sulfate 3) Ammonium Phosphate

Naming Ternary Ionic Compounds CaCO 3 PbCrO 4

Formulas of Molecular Substances A substance whose atoms are held together by covalent bonds Electrons are shared by two atoms Same two elements may form several compounds

Formulas of Molecular Substances A system of prefixes are used to distinguish between the compounds…. mono – one (1)hexa – six (6) di – two (2)hepta – seven (7) tri – three (3)octa – eight (8) tetra – four (4)nona – nine (9) penta – five (5)deca – ten (10)

Formulas of Molecular Substances Naming: use prefixes and -ide ending for 2 nd atom NO 2 1 atom N & 2 atoms of O (nitrogen) & (di + oxide) Nitrogen dioxide ** Only use Mono on the 2 nd atom

Practice with Molecular Compounds SO 2 N 2 O 4 CCl 4

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