Chemical Names and Formula Chemistry Cook

Periodic Table There are over 90 naturally occurring elements/atoms and about 25 elements made in the lab. Various combinations of atoms can be formed, and which such diversity we need a way to name and communicate these variations

Periodic table Elements are arranged in row and columns on the: Periodic table Hydrogen, the smallest and lightest element in top right corner Helium is atomic number 2

Atomic Numbers Krypton

Calculate For any element: Number of Protons = Atomic Number Number of Electrons = Number of Protons = Atomic Number Number of Neutrons = Mass Number - Atomic Number For krypton: Number of Protons = Atomic Number = 36 Number of Electrons = Number of Protons = Atomic Number = 36 Number of Neutrons = Mass Number - Atomic Number = 84 - 36 = 48

Periodic Table A column of elements in the periodic table is known as a group There are 18 groups Group 1A: H Li Na K RB Cs

Breakdown of each group Group 1=Alkali Metals Group 2= Alkaline Earth Metals Group 3-12= Transition metals Group 13,14 & 15= Other metals Metalloids=Boron diagonal down over and down over( A big L) Group 14-16 =Non Metals Group 17= Halogens (salt formers) Group 18= Noble gases Rare Earth Metals= Man made elements inserted in the transition metal at 56 and 88 Chemical Elements.com - Noble Gases

Alkali Metals/Representative metals (A) The illustrate the entire range of chemical properties Both metals and non metals They do not include transition metals or inner transition metals (man made ones)

Metallic Metals A Groups (1, 2 13-18) Have high luster when cleaned High electrical conductivity Ductile Can be drawn into wires Malleable Beaten into sheets (dyes at GM plants)

Groups 1A starts with H or Li 2A starts with Be 3A starts with B Hydrogen is special It is a non metal in group 1A 2A starts with Be 3A starts with B 4A starts with C 5A starts with N 6A starts with O 7A starts with F

Transition Metals (B) B group elements Inner transition metals (rare earth metals).

Non Metallic Elements that are: Non lustrous Poor conductors of electricity Some are gases Others are brittle solids and some liquids at room temperature

Semi Metals or Metalloids Elements with the properties of both metals and nonmetals Silicon Found in transistors Good semi conductor Conducts electricity in a special way Breast implants (cheap ones)

Atoms and Ions All elements are composed of atoms of the same kind Atomic Theory (review) An atom is electrically neutral because it has an equal number of protons and electrons Na atomic number is 11 and has 11 protons and is positively charged, has 12 neutrons Because Neutrons have no charge the total charge of Na is (+11)+ (11)=0 When elements form compounds they can gain or lose electrons, and when the number of electrons is not equal to the number of protons then the atom becomes a Ion

IOns Are atoms or groups of atoms that have a positive or negative charge Formed when atoms gain or lose electrons

Positive ions Metals tend to form positive ions by losing one or more electrons Cation Any atom or group of atoms with a positive charge Na ion is form by the loss of one electron from the Na atom Sodium ion has 11 protons and 10 electrons it has a charge of 1+ Atomic charges are written with the number followed by a sign Na1+ or Na+ (always write ions this way) If the number is 1 it can be omitted

Ions Mg ions are formed differently because they have different valence electrons (electrons in outer shell) Mg has a charge of 2+ so it has 12 protons, and 10 electrons

Negative Ions Nonmetallic elements tend to gain one or more electrons Anions Atoms or groups of atoms with a negative charge Anions have more electrons (unlike cations). Cl ions has 17 protons and 18 electrons It has a charge of -1 Oxide ion has a charge of -2

Compounds Are pure substances the differ from elements because they contain more than one kind of atom. Law Of Definite Proportions: In any chemical compound the elements are always combined in the same proportion by mass A Molecule is a neutral group of atoms that act as a unit. All molecules of a given compound are neutral. Compounds that are composed of molecules are molecular compounds.

Law of Definite Proportions MgS is a compound. IF we have 100g of this compound It will always contain: 43.13g of Mg 56.87g of S This mass ratio will never change no matter how much you have

Chemical Formulas There are more than 4 million chemical compounds. Some are molecular Some are ionic A chemical formula shows the number and kinds of atoms present in a molecule. A molecular formula shows the number and kinds of atoms present in a molecule of a compound Example = H2O CO2 C2H6 C2H6O

Formulas and Names of Common Metals Ions with more than 1 ionic charge Formula Name Stock Name Classical Name Cu1+ Copper (I) Ion Cuprious ion Cu2+ Copper (II) Ion Cupric Ion Fe2+ Iron (II) Ion Ferrous Ion Fe3+ Iron (III) Ion Ferric Ion Hg2 Mercury (I) Ion Mercurrous Ion Hg2+ Mercury (II) Ion Mercuric Ion Review Table 5-3

Rules for naming Compounds that give OH- ions Bases Compounds that give H+ ions Acids ite ending Will always indicate less oxygen ate ending Will always indicate more oxygens

Binary ionic compounds Composed of two elements Always cation and anion They always have ide ending Name metal first then put ide ending on nonmetal Sodium chloride Monoatomic always have ide ending

Binary Ionic compounds Name by writing name of cation followed by name of anion (ide ending).

Ternary Ionic Compounds Contain 3 different elements They usually contain one or more polyatomic ions First write down formulas of ions Then balance charges An ate or ite ending on polyatomic ion Calcium nitrate

Acids Are compounds that give off hydrogen ions when dissolved in water. When anion ends in ide the acid name begins with prefix hydro. The stem (nonmetal in most cases ends with ic) HCl= hydrochloric acid

rules Anion ending Example/Stem Acid Name Example ide Cl- Chloride Hydro (stem) ic acid Hydrochloric acid ite SO2-3 Sulfite (stem) ous acid Sulfurous acid ate NO-3 nitrate (stem) ic acid Nitric acid