Honors Chemistry
1 st Semester Final Exam Review 2014-2015
The structure of the atom
Name : _____________________
Subatomic particles- know location and how to calculate amounts given atomic number or atomic mass
Atomic number = number of protons = number of electrons for a neutral atom identifies what the element is. All atoms of the same element have the same atomic number!
Atomic mass = protons + neutrons
Isotopes- same number of protons and electrons, different number of neutrons; therefore mass number different, atomic number the same. Be able to distinguish how two isotopes differ. I.e. Carbon –12 and Carbon-14
Be able to view a picture of an atom and determine its charge, atomic number, atomic mass
Ion- charged particle resulting from the gain or loss of electrons. Results in an unequal number of electrons and protons in the atom o Positive ions = cations o Negative ions = anions o Be able to explain what happens to any element in the P-Table to form an ion
Lab Safety
Bunsen burners- how do you safely light a burner?
Luminous vs. Non-luminous flames- which can you read by? Which represents complete combustion of the gas? Which is the hotter flame?
Lab Skills
Measurement- what is significant in a measurement? Measure to the readable value and estimate the last digit
Volumetric measurement- Know how to read the meniscus
Be able to identify basic lab equipment and know its use which piece of glassware is most appropriate for which task?
Significant digits- be able to determine the number of sig figs. in a number or for a final answer in a calculation
Know your rules for sig figs and sig fig calculations!- Alt – Pac Rule . +/- determine the lowest decimal
position. X and / lowest number of significant figures.
Appreciate that the electron can be considered to have wave like properties as well as particle like properties
Understand the concept of electrons in regions of probability and use quantum numbers to explain the location and characteristics of electrons
Valence electrons Vs kernel electrons o Valence electrons determine the chemical reactivity of the atom
Ground state electrons Vs excited state electrons o Photons, quanta, bright line spectrum vs. continuous spectrum
Electron configurations
Be able to identify elements based on their electron configurations o o Recall and understand the rules for filling orbitals and determining electron configurations including the Aufbau principle, the o
Pauli exclusion principle and Hund’s rule.
Be able to determine the electron configuration (Noble gas configuration) of the most common ion of an atom o Be able to identify the location of the element in the periodic table based on its electron configuration
The Periodic Table o Know the 1 st periodic table was developed by Mendelev and the modern periodic table was developed by Mosley o Understand the regular, repeatable patterns occur across periods and within groups on the periodic table o o
Basic layout- periods (horizontal rows) vs. groups (vertical columns)
Know the names and basic properties of the groups in the periodic table
1A = Alkali Metals = most active metals
2A = Alkaline Earth Metals
1B –10B = Transition Metals
Metalloids = staircase separates the metals from the nonmetals – has characteristics of each
7A = Halogens = most active nonmetals
8A = Noble Gases
Lanthanide and Actinide series
Know the blocks in the P-Table = s, p, d, and f and be able to use electron configurations with the P-Table o o Know the types of ions that form in the various groups- i.e. Metals will form cations, nonmetals will form anions
Trends in the P-Table
Recall the definition of effective nuclear charge and shielding and use these terms to describe the trends below o Electronegativity- ability of an atom to attract another atom’s valence electrons. Decreases down a group, increases across a period
o Ionization energy- energy necessary to remove an atom’s outer shell electrons. Decreases down a group, increases across a period o Atomic radius- increases down a group, decreases across a period o Know how to use the P-Table to determine the oxidation number of an element this will help tremendously when it comes to writing formulas!
Atoms bond to gain stability octet rule Nobel Gas configuration
Ions- formed from the gain or loss of electrons
Cations = + ions
Anions = - ions
Ionic Bonds- formed as a result of the electrostatic force (attraction of oppositely charged ions)
Ionic Compounds are Crystals organized into an array- regular geometric pattern
Ionic compounds are NOT molecules!
Know how to draw a Lewis Dot diagram for atoms and show the transfer of electrons in an ionic bond
Know how to name ions and ionic compounds
Anions- replace the ending of the element with “-ide” ion
Cations- name element and include the word ion
Use Table F to name polyatomic ions or determine their oxidation numbers
Binary compounds- cation followed by name of anion
Ionic Compounds-
Metals + nonmetals or substances that contain polyatomic ions
Transfer electrons
Naming
Binary ionic compounds- metal first, add nonmetal + suffix “-ide”
Polyatomic ionic compounds- metals first, add name of polyatomic (see TABLE E)
*NOTE: if the ionic compound contains a transition metal, Roman numerals are used in the name to show the metal’s charge. examples: FeCl
2
FeCl
3
– Iron (II) chloride
– Iron (III) chloride
)
3
– Gold (III) sulfate Au
2
(SO
4
Writing formulas
Metal ion first, then nonmetal
Look up oxidation numbers
Crisscross method- used with binary and polyatomic ionic compounds
Mg +2 + Cl MgCl
Li + + MnO
4
2 Li
2
2
MnO
4
Covalent Compounds-
Nonmetal + nonmetal
Share electrons
Naming
Least electronegative element first, second element add suffix “-ide”
Use prefixes to indicate number of atoms in each molecule
SO
3
NO
2
– Sulfur trioxide
– Nitrogen dioxide
Writing formulas
Least electronegative element first
Use prefixes to determine the numbers of atoms
Carbon dioxide – CO
2
Carbon tetrachloride – CCl
4
Write Empirical formulas- lowest whole number ratio of atoms in a crystal
Determine Molecular formulas for covalent compounds
Covalent compounds- share electrons to form bonds
Octet Rule also applies to covalent compounds
Draw structural formulas for covalent compounds remember double and triple bonds are possibilities in drawing structural formulas
Covalent compounds can form multiple bonds- double and triple
Know exceptions to Octet Rule- Boron and Sulfur
Know how to name covalent compounds- use prefixes
Polarity
Know how to determine bond polarity vs molecule polarity- molecules can have polar bonds, but are symmetrical in shape and therefore nonpolar molecules
VSEPR- valence shell electron pair repulsion theory- electrons want to get as far away from each other as possible- form specific shapes with max distance between electrons
Use Structural formulas to determine the number of electron pairs around the central atom
Count the number of lone and bonding pair electrons to determine the VSEPR numbers and the molecule’s shape
The shape of the molecule will determine the molecules’ polarity
Asymmetrical molecules are polar
Symmetrical molecules are nonpolar
Comparison of Ionic Vs Covalent Substances
Ionic Substances
High melting points- due to strong electrical attraction of the ions for one another
Dissolve in water
Covalent Substances
Lower melting points than ionic substances- weaker bonds
Some will dissolve in water, some do not (Polar Vs
Nonpolar)
Form crystals
Hard and brittle
Conduct electricity in solution (dissolved in water- aqueous) and in the liquid phase
Do not conduct electricity in solid phase because of the rigidity of the crystal
Soft solid phase
Some conduct electricity in aqueous phase, but not as well
as ionic substances (Polar Vs Nonpolar)
Do not conduct electricity in liquid or solid phase
Matter has a natural tendency to be disordered (have a great deal of entropy). If a substance is to be held in the solid or liquid phase, then some sort of force must be present to keep the individual atoms, molecules, or ions in the solid or liquid in place. In other words, these forces prevent particles from “flying around” randomly, as they do in gases. These forces are called intermolecular forces
Metallic substances- positive ions immersed in a sea of electrons
Mobility of electrons gives the metals their characteristics
Atomic mass vs molecular mass vs molar mass- remember molar mass is the heaviest- g/mol
Perform mole conversion without mole map
Define a mole
Determine number of atoms or moles of atoms within a molecule using molecular formula- Cu(C
2
H
3
O
2
) moles of atoms?
Percent composition calculations from chemical formulas
Determine empirical formulas from percent by mass
Determine molecular formulas from empirical formula and molecular mass
2
- how many total
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