SOL Items
- Density formula D=m/v so for v= m/D
- Volume= L x W x H= units3
- Area formula: L x W= units2
- mass: m= D x v
- K=oC+273.16
- oC: K-273.16= oC
- Percent Error= (your value-literature value)/literature value x 100 (Units are in %)
- Energy Conversion of calories to joules: 0.2390 calories (cal) = 1 Joule (J) and 1 cal=4.184 J
- Atmosphere to Pascal: 1atm=101,305 Pa
- Physical Properties to remember: mass, length, volume,color, density, malleability, ductility, and conductivity, crystalline shape, melting point, boiling point, refractive index.
- Accuracy vs. Precision: Accuracy-Refers to how close the measurement is to the actual value while Precision refers to how close a set of measurements is together whether or not the measurements are correct
- Separation of Mixtures:
- Distillation-occurs when a liquid is boiled to produce a vapor that is then condensed again to a liquid. This causes the solid substances that were originally dissolved to stay in the original container and the water to go into a second receiving container.
- Chromatography-Involves a solid (stationary phase) and a liquid or gas (mobile phase). The separation occurs because the liquid or gas has a faster rate than the solid.
- Paper Chromatography-paper (solid) and a liquid are involved. The liquid travels up the paper and separates according to the heaviness of the individual parts of the liquid
13.Antoine Lavoisier a French Chemist (1743-1794)
Proposed the Law of Conservationof Mass: in ordinary chemical reactions, matter can be changed in many ways, but it cannot be created or destroyed.
- Find on Periodic table: Atomic Number and Atomic Mass, and figure out Neutron #, Electron # and charge is negative, and Proton # and charge is positive.
- Atomic Mass (Symbol Z) –Atomic number (Symbol A)=neutrons Z-A=Neutrons (neutrons have no charge and are found in the nucleus with the protons)
- Note: Atomic number + neutrons =Atomic mass
- Average Atomic Mass
Percent (in decimal form) times Atomic Mass for each one and then add the total
- Rutherford's Gold Foil Experiment:
- That the atom is mostly empty space
- And that the nucleus is positive charged (because of protons) and contains almost all of the mass of the atom.
- Alpha radiation is radiation that was deflected toward the negatively charged plate alpha radiation.
- Made up of 2 alpha () particles
Each alpha particle contains 2 protons and 2 neutrons
Has a 2+ charge
Has a mass of 4 amu
- Ex.: Ra- 88 (Radium-226) 86 Rn (radon-222) + 4 He (alpha particle) (Exact model will be shown in class)
- Beta radiation is radiation deflected toward the positively charged plate beta radiation.
- Consist of fast moving electrons known as beta () particles.
Each beta particle contains an electron with a -1 charge.
- Ex.: C-14/6 14N/7 + 0/+1e
- Half Life Formula
Amount Remaining= Original Amount of parent ÷ 2n n=half-life
- Electron Configuration-The arrangement of electrons in an atom. The order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 8s
Rules:
- Octet law: only a maximum of 8 electrons on the outermost shell (2 in the 1st level)-known as the valance electron number
- The aufbau principle states that each electron occupies the lowest energy orbital available
- In order of increasing energy, the sequence of energy sublevels within a principal energy level is s (2 e-), p (6 e-), d (10 e-), and f (14 e-).
- The Pauli exclusion principal states that a maximum to 2 electrons may occupy a single atomic orbital, but only if the electron has opposite spins.
Represented as ↑↓
- Periodic Trends:
- Atomic Radius-Deals with the size of an atom
- It decreases as it moves across a period
- Increases as it moves down the Group
- Electronegativity-The attraction it has to bond with other elements- F has the highest
- It decreases as it moves down a group and increases as it moves across a period
- Periodic table/Element items:
Dmitri Mendeleev put together the 1st periodic table-Table not completely correct
A period in the periodic table is all the elements in a horizontal row.
A group in the periodic table is all the elements located in the same vertical column, which is assigned a number from 1-18.
METALS
Usually shiny when smooth and clean
- Conduct heat and electricity well
- Solid at room temperature
- Most are also ductile and malleable (meaning they can be pounded into thin sheets and drawn into wire.)
- Chemically reactive
- Positively charged
- These atoms have only a few electrons in the outer level.
- Have a tendency to lose their electrons in the outermost level.
- Alkali metals: Group 1 except H
- They react with water
- Easily lose a valence electron and form an ion with a +1 charge.
- Ends in sublevel s1
- Alkaline Earth metals: Group 2
- Reactivity similar to Alkali metals but not as great
- +2 charge
- Ends in sublevel s2
- Aluminum Group (Sometimes called the Boron Group)
- Group 13
- +3 charge
Transition Elements for divided into 2 set:
- Transition metals
- Any element in columns 3-12
- Has 2 electrons in the outer level - 4s2
- Elements with #'s 22-28 also have a 3d sublevel
- In all groups except 12, the dorbitals are only partially filled.
- Share properties such as electrical conductivity, luster, and malleability with other metals.
- They have magnetism
- Inner transition metals: Lanthanoid Series and Actinoid Series
- They are the highest energy electrons (f electrons) are inside the d sublevel and the outer level.
- Both have outer shells consisting of an s2 sublevel
Lanthanoid Series- Lanthanum (57) to Ytterbium (70)
- Electrons are added to the 4f sublevel instead of the sixth or outer level
- Are silvery metals with relatively high melting points
- Used extensively as phosphors, substances that emits light when struck by electrons.
Actinoid Series-Actinium (89) to Nobelium (102)
- This series have an increasing # of electrons in the 5f sublevel
- They are all radioactive.
NONMETALS
- These are usually gases or brittle solids at room temperature.
- Dull appearance
- Insulators
- Outer electrons are held closely by the nucleus
- Form negative ions (anions)
- Have 5 or more electrons in the outer level than metals.
- They often gain electrons or share their electrons in the outermost level.
Group 14: Carbon Group
- Allotropes are found in this group: forms of an element in the same physical state that have different structures and properties.
- Ex. Carbon in the form of coal, Diamonds and graphite
- Silicates are silicon compounds bound to Oxygen, and each Si atom is surrounded by 4 O atoms.
Group 15: The Nitrogen and Phosphorus Group
- There are nonmetals (N and P), metalloids (As and Sb), and metals (Bi)
- Each has 5 valence electrons and have many different properties
- Charge is -3
Group 16: The Oxygen Group or Chalogens
- Have 2 allotropes: Ozone, and O2
- Some are oxides known as amphoteric: Those that can produce either acidic or basic solutions. Ex. Sulfur compounds like sulfuric acid (H2SO4)
- Charge is a -2
The highly reactive Group 17 elements are called Halogens
- Fluorine is the most reactive element- Highly electronegativity
- Halogens make salts
- Have 7 valence electrons and often tend to share one electron or gain one.
- Have a 1- charge so they react with Group 1 the most
The extremely nonreactive Group 18 and is known as Noble gases.
- All except Helium have 8 electrons in their outer level.
METALLOIDS
These are elements with physical and chemical properties of both metals and nonmetals.
Silicon and germanium are used a lot in making computer chips and solar cells.
Staircase elements between metals and nonmetals
Are often brittle solids
- Oxidation Number
For metals
- Positively charged
- in Group 1-2: Same as Group number
- in Groups 3-12: number varies
- Ex. Hydrogen is in Group 1 and the Oxidation # is +1
- Ex. Magnesium is in Group 2 and the Oxidation # is +2
For nonmetals
- Negatively charged
- Find valence electron number: 2nd number of group #
- Formula: -8+valence electron number
- Ex. Oxygen is in Group 16, -8 + 6= -2
- Ex. Nitrogen is in Group 15, -8 + 5= -3
- Ex. Chlorine is in Group 17, -8 + 7= -1
For Metalloids
- Positively charged
- Find the number the same way and nonmetals
- Ex. Carbon is in Group #14 and the Oxidation # is +4
- Ionic Bond Notes
Properties
- Ionic Bonds are formed by a cation (positive charged metal) bonded to an anion (negative charged nonmetal)
- Metal loses one or more electrons
- Nonmetal gains one or more electrons
Note: Static electrical attraction is the basis for ionic bonds, because the positively charged ion
(cation) is attracted to the negatively charged ion (anion)
- High Boiling and High Melting point
- Forms a 3-D crystal lattice
- Crystal lattice bonds are strong and take lots of energy to break the bonds
- Usually poor conductors of electricity
- Because they are solid and rigid the ions can’t move freely
- Only good conductors if dissolved in an aqueous solution where they become electrolytes
- Don’t consist of molecules
- Strongly bonded
- Can form a salt
Ionic Terms
- Ion: charged particle
- Anion: negatively charged ion
- Cation: Positively charged ion
- Salt: An ionic compound that forms when a metal atom or a positive radical replaces the H of an acid.
- Ex. NaCl
- Salts are excellent conductors of electricity because they are brittle solids that can easily be dissolved in an aqueous solution such as water
Ionic Bonding Problems/Diagrams
- Na (+1) + Cl (-1) → NaCl
- Ca (+2) + Cl (-1) +Cl (-1) → CaCl2
- Naming Ionic Compounds
Many Ionic compounds contain polyatomic ions: ions made up of more than one atom.
- Polyatomic ions exist as a unit, so never change the subscript
- If you have to balance an ionic compound with a polyatomic ion then ( )and a subscript must be written
- Ex. Ca (+2) and PO4 (-3) →Ca3(PO4)2 and named Calcium phosphate
- Most polyatomic ions are oxyanions
- Oxyanion is a polyatomic ion composed of an element, usually a nonmetal, bonded to one or more oxygen atoms
- If a transitional metal and a polyatomic ion is involved
- Ex. Cu (+2) and NO3 (-1) →Cu(NO3)2 and named Copper (II) nitrate
- Note that transitional metals with varying oxidation numbers always have to state which atom was used in the chemical compound whether or not a polyatomic ion is used
Rules for Naming Ionic Compounds
- Name the cation (metal) first and the anion (nonmetal) second
- Monatomic cations use element name
- Monatomic anions take their name from the root element name plus the suffix –ide
- Ex. CsBr is Cesium bromide
- Determine oxidation numbers of transitional metals compounds before naming to determine Roman number I-IV
- Ex. Fe2O3 is Iron (III)oxide
- Some transitional metals only have one charge
- Cadmium: Cd+2
- Zinc: Zn+2
- If the compound has a polyatomic ion, simply name the ion
- Ex. NH4Cl is Ammonium chloride
- If the polyatomic ion has an oxyanions
- The ion with more oxygen atoms is named using the root of the nonmetal plus the suffix –ate
- Ex. NO3- is nitrate
- Ex. ClO3- is chlorate
- Ex. CO3-2 is carbonate
- The ion with fewer oxygen atoms is named using the root of the nonmetal plus the suffix –ite
- Ex. NO2- is nitrite
- The oxyanions with the greatest number of oxygen atoms is named using the prefix per-, the root of the nonmetal, and the suffix-ate
- ClO4- is perchlorate
- IO4- is periodate
- MnO4- is permanganate
- The oxyanions with one less oxygen atom is named with the nonmetal and the suffix-ate
- SO4-2 is sulfate
- The oxyanions with two fewer oxygen atoms is named using the root of the nonmetal plus the suffix –ite
- Ex. ClO2– is chlorite
- The oxyanions with three fewer oxygen atoms is named using the prefix hypo-, the root of the nonmetal, and the suffix –ite
- Ex. ClO– is hypochlorite
- Polyatomic ions with 2 transitional metal atoms include a Di-prefix
- Ex. H2PO4- is Dihydrogen phosphate
- Ex. Cr2O7-2 is Dichromate
- Some Hydrogen plus a polyatomic ion are named two ways
- Ex. HSO4- can be named bisulfate or Hydrogen sulfate
- Ex. HCO3- can be named bicarbonate or Hydrogen carbonate
- Covalent Bonds
Properties
- Nonmetal + Nonmetal (usually)
- Most common type of bond
- Covalent bonds form molecules
- Form by sharing electrons
- The sharing of one pair of electrons is a single bond (X-X)
- Another name for single covalent bond is sigma bond symbolized by σ
- Sigma bonds form from the overlap of a s orbital with another s orbital, a s orbital with a p orbital, or a p orbital with another p orbital
- The sharing of two pairs- double bond (X=X)
- Another name for multiple bonds is pi bond symbolized by π
- Pi bonds form when parallel orbitals overlap to share electrons
- A double covalent bond has one sigma and one pi bond
- The sharing of three pairs-triple bond (XΞX)
- A triple covalent bond has one sigma and 2 pi bonds
- Bond polarity explains the attraction between the sharing
- Nonpolar electrons are shared equally Ex. F-F (same electronegativity)
- Polar electrons are not shared evenly Ex. H-F (different electronegativity)
Intramolecular Forces in Bonds Table
Force Basis of attractionIonic cations and anions
Covalent positive nuclei and shared electrons
Metallic metal cations and mobile electrons
Intermolecular Forces
Intramolecular forces do not account for all attractions between particles. There are forces of attraction called intermolecular forces.
- They can hold together identical particles or two different types of particles
- Also called van der Waals forces
3 types:
- Dispersion forces
- Sometimes called London dispersion forces
- The force between oxygen molecules
- Weak forces that result from temporary shifts in the density of electrons in electron clouds:
………
Attraction
Temporary attraction Temporary attraction
←|-←|-
- Dipole –dipole: Attraction between oppositely charged regions of polar molecules
- Stronger than dispersion forces
- The more polar the molecule, the stronger the force
- Hydrogen bonds: One special type of dipole-dipole dealing with hydrogen bonds
- Very strong intermolecular force that is formed with a H end and a F, O, or N atom on the other dipole
Many physical properties of covalent molecular solids are due to intermolecular forces.
- The melting and boiling points are relatively lower than Ionic (that is why salt doesn’t burn when you heat it but sugar will)
- Many are gases are vaporized at room temperature
- Hardness is also due to the intermolecular forces so covalent solids are soft in comparison to ionic solids
Naming Molecular Compounds: Rules for Binary Molecular Compounds are similar to that of naming Ionic compounds except the names include prefixes indicating the number of atoms in the molecule.
Numerial Prefixes
- Mono-1
- Di-2
- Tri-3
- Tetra-4
- Penta-5
- Hexa-6
- Hepta-7
- Octa-8
- Nona-9
- Deca-10
Exceptions:
H2O is water
NH3 is ammonia
Examples:
- CO2 –Carbon dioxide
- CO-Carbon monoxide
- N2O4-dinitrogen tetroxide
- SCl6 –Sulfur hexachloride
- Naming Acids and Bases
Binary acids are acids with only two elements.
Prefix –hydro, stem of anion, and suffix –ic
Exception is HN3: Hydroazoic acid, where the root – azo is used for nitrogen.
Ternary acids are acids that contain 3 elements.
Usually no prefix is used and the suffix is –ic.
Exceptions:
One less O than the most common : no prefix and suffix used is –ous
Two less O than the most common: prefix hypo- and suffix –ous
One more O than the most common: prefix per- and suffix –ic
Ex. HClO3 is the most common: Chloric acid
HClO2 has one less O so: Chlorous acid
HClO has two less O so: Hypochlorous acid
HClO4 has one more O than most common so: Perchloric acid
Ternary bases
Arrhenius bases are composed of metallic, or positively charged ions and the negatively charged hydroxide ion. Therefore, these bases are named by adding the word hydroxide to the name of the positive ion.
Ex. Sodium hydroxide is NaOH.
- Characteristics of Acids and Bases
Acids
- Liquids are tart, sour, or sharp tasting
- They conduct electricity (in solutions)-electrolytes
- They produce H2 gas
- Usually in liquid or gas form
- pH is 0-6.9
- Strong acid-have a low pH and completely ionized in an aqueous solution
- The closer the substance’s pH is zero the stronger the acid
- Weak Acid-have pH closer to 6.9 and are only slightly ionized in an aqueous solution
- They react to metals-corrosive
Bases
- Commonly found in solid form
- Chemical formula except for NH3 has OH on the end
- pH range is 7.1-14
- Strong base-dissociates completely into metal ions and OH- ions in aqueous solution
- The closer the substance’s pH is 14 the stronger the base
- Some are not very soluble in water
- Weak base-react with water to form the OH- ion and conjugate acid of the base
- Some are insoluble in water while others are soluble
- Slippery feel because bases react with oils in your skin-soaps and cleaning agents
- Are electrolytes
Three primary theories of acids and bases
Theory / Acid definition / Base DefinitionArrhenius / Any substance that releases H+ ions in water solution / Any substance that releases OH- ions in water solution
Bronstead-Lowery / Any substance that donates a proton / Any substance that accepts a proton
Lewis / Any substance that can accept an electron pair / Any substance that can donate an electron pair
Examples:
I.)Arrhenius acid: HCl (g)→H+(aq) +Cl-(aq) Arrhenius base: NaOH (cr) →Na+ (aq) + OH-(aq)
II.)Bronstead-Lowery: HCl (g) + H2O → H3O+(aq) + Cl-(aq)
Acid +base→conjugate acid + conjugate base
- Conjugate acid-is the particle formed when a base gains a H+ ion
- Conjugate base-is the particle that remains when an acid has donated a H+ ion
- Conjugate acid-base pair-consists of 2 substances related by the gain or loss of a single H+ ion
III.)Lewis: H3N: (Lewis base) + BF3 (Lewis acid) → H3N: BF3 (Product)
pH
- pH is a measurement of the H3O+ ion concentration of an acid or a base.
Problem Formulas: (Actual problem examples will be stated in class)
1.)pH=-log[H+]
2.)pOH=-log[OH-]
3.)pH + pOH=14
4.)[H3O+]=10-pH use antilog
5.)[OH-]=10-pH
6.)[OH-]=antilog (-pOH)
7.)Kw=[OH-] x [H+] which equals 1 x 10-14M
Titration
Titration-is a procedure used to bring a solution of a known concentration into a reaction with a solution of an unknown concentration in order to determine the unknown concentration or the quantity of the solute in the unknown.