Title: Chem Review 3 PART 1 TOPIC: HISTORY OF PERIODIC TABLE EQ: How was the first PT organized and how has it changed over the years?
Title and Highlight Topic: EQ: Date Reflect Question: Reflect on the material by asking a question (its not suppose to be answered from notes) NOTES: Write out the notes from my website. Use different types of note-taking methods to help you recall info (different color pens/highlighters, bullets, etc) When I lecture we will add more info, so leave spaces in your notes DRAW ANY PICTURES, FIGURES, AND WRITE OUT ANY PRACTICE PROBLEMS/QUESTIONS. WE WILL ANSWER THEM TOGETHER. So LEAVE SPACES SO WE CAN ANSWER QUES. Summary (end of notes) : 1-2 Sentences of what you learned
The periodic table is the most important tool in the chemist s toolbox! Why is the Periodic Table important to me? You get to use it on every test. It organizes lots of information about all the known elements.
Dmitri Mendeleev: Father of the Periodic Table In 1869 he published a table of the elements. 1834-1907
A first look at the periodic table Dmitri Mendeleev organized all of the elements that were known at the time into rows and columns based on their chem/phy similarities and their masses.
Periodic Table The table is called periodic because the pattern of similar properties repeats as you move from period to period.
HOW HIS WORKED 70 known elements. Dmitri Mendeleev Organized rows (periods) by increasing atomic weight. Put elements in columns (groups) by their properties. SOME PROBLEMS He left blank spaces for undiscovered elements. (Turned out he was right!) He broke the pattern of increasing atomic weight. Used his P.T. to predict the physical properties of three elements that were yet unknown.
Problems arose when new elements were discovered. Looking at our modern P.T., can you identify what problems might have caused chemists a headache? Ar and K Co and Ni Te and I Th and Pa
The fact that Mendeleev s predictions for Sc, Ga, and Ge were amazingly close to the actual values, his table was generally accepted.
Henry Moseley In 1913, through his work with X-rays, he determined the atomic number of the elements* elements should be arranged in order of increasing atomic number is known as the periodic law. 1887-1915
Glenn T. Seaborg After co-discovering 10 new elements, in 1944 he moved 28 elements out of the main body of the periodic table to their current location below the main part of the P.T. :Lanthanide and Actinide series. 1912-1999
Current Periodic Table:
How the P.T. has changed over time? Past P.T. Increasing Mass number (not any more!!!) Still the same!!! Current P.T. Increasing ATOMIC NUMBER!! Elements in the same group have similar chemical and physical properties!! Elements in the same group have similar chemical and physical properties!! (Mendeleev did that on purpose.)
Title: Chem Review 3 PART 2 TOPIC: ORGANIZATION OF PT EQ: How is the PT organized and why is it useful for us studying chemistry?
Students. The next 6 slides are notes about the Periodic Table and how it is organized. You can either make a sketch (please don t draw every box) for each slide OR Make one BIG (entire page) Sketch and label all notes on that one sketch. Your choice!
The horizontal rows of the periodic table are called PERIODS (7). Make a Sketch with notes
The elements in any group have similar physical and chemical properties! The vertical columns are called GROUPS (18), or FAMILIES. Make a Sketch with notes
1A 2A Elements in the 1A-8A groups are called the representative or main group elements Make a Sketch with notes 3A 4A 5A 6A 7A 8A
The group B are called the transition elements Make a Sketch this with notes
Types of Elements Sketch this with notes The elements in the periodic table can be broadly classified as metals, nonmetals, and metalloids.
3 classes of elements - METALS Located to the left of the dark zig-zag line All Solids!!! Except one who is it?? shiny surface Tend to be white/gray/silvery (common exceptions: copper and gold) malleable (you can pound it into a flat sheet) ductile (you can draw it into a thin wire) good conductors (heat/electricity) Metals tend to LOSE electrons in chemical changes.
3 classes of elements - NONMETALS Located to the right of the dark zig-zag line. dull surface brittle sulfur Some are solids and some are gases. Only 1 liquid. good insulators and poor conductors Nonmetals tend to GAIN electrons in chemical changes. Vary in color (P - red/white, S yellow, C black/clear, I purple, Br brownish red, etc) Sketch this with notes
3 classes of elements METALLOIDS (only 8) Located on the border of the dark zig-zag line. the dividing line between metals and nonmetals. All SOLIDS! Also called semimetals Behave (chemically) as nonmetals, but look physically & electrical conductivity resembles metals. Semiconductors they do conduct some heat/electricity Used in computers, cell phones, and other modern gadgets. silicon Sketch this with notes
Hydrogen Hydrogen belongs to a family of its own. Hydrogen is a nonmetal!!! It s a diatomic, reactive gas. Facts Hydrogen was involved in the explosion of the Hindenberg. Hydrogen is promising as an alternative fuel source for automobiles
Group 1 - Alkali Metals (not H!!!) Very reactive metals (solids) with air and water Never found pure in nature, too reactive (always combined with something else in nature like in salt). All have one valence e- Soft enough to cut with a butter knife Reactivity of these elements increases down the group Alkali Metal Family Video Clip Sketch this with notes
Group 2 - Alkaline Earth Metals Reactive metals (solids) that are always combined with nonmetals in nature. Not found pure in nature (too reactive but less reactive than alkali metals) Alkaline means basic All have 2 valence e- Mg and Ca important for our body!!! Also, used in batteries Sketch this with notes
Groups 3-12: Transition Metals Sketch this with notes
Transition Metals Groups 3-12 All solids except Mercury Less reactive harder metals Includes metals used in jewelry and construction. Metals used as metal.
Group 14 - Carbon Family 4 Valence e- Elements important to life and computers (Si and Ge). Carbon is the basis for an entire branch of chemistry called ORGANIC Chem. Sketch this with notes
Group 15 - Nitrogen Family Sketch this with notes 5 valence e- Nitrogen makes up over 80% of the atmosphere. Nitrogen and phosphorus are both important in living things. The red stuff on the tip of matches is phosphorus.
Group 16 - Oxygen Family or Chalcogens 6 valence e- Oxygen is necessary for respiration. Many things that stink, contain sulfur (rotten eggs, garlic, skunks,etc.) Sketch this with notes
Group 17 - Halogens 7 valence e- Very reactive, diatomic, nonmetals Not found pure in nature Always combined with other elements in nature. Used in some light fixtures Used as disinfectants and to strengthen teeth. Sketch this with notes
Group 18 - Noble Gases 8 valence e- (except He has 2 e-) VERY unreactive, monatomic gases Only elements found pure in nature Colorless, odorless, and unreactive; Don t form compounds!!! (These are also called Inert gases ) Used in lighted neon signs and balloons. Sketch this with notes
A l k a l i M e t a l s A l k a l I n e E a r t h M e t a l s N o b e l G a s e s H a l o g e n s Transition Metals Inner Transition Metals Representative Elements Transition Elements Representative Elements METALS Periods Groups Nonmetals
QUESTIONS
Title: Chem Review 3 PART 3 TOPIC: ISOTOPES EQ: What part of the atom changes when you have isotopes of elements?
The Mass Number (A), (rounded to the nearest integer) Mass# = p + + n o # of neutrons = mass # p + Atomic number (Z). Protons determines the identity of the element. A# = p + = e - (atoms are neutral)
Isotopes: When the Number of Neutrons & Mass # Varies All atoms of an element have the same # of protons. Atoms with the same # of protons but different # of neutrons (this causes the mass # to also change) are called isotopes.
EXAMPLE OF AN ISOTOPE ATOMIC MASS 35 Cl 37 Cl 17 17 18 NEUTRONS 20 NEUTRONS ATOMIC NUMBER
So Atomic# = p + = e - (if atom is neutral) HOWEVER..what if the atom is not neutral?
When electrons are lost or gained, IONS are formed. And electrons won t equal protons no more!!! Atomic# = p + = e - Electrons Electrons can be lost or gained = Chemical Reaction, which make up more than 99% of all rxns in life)
Ions: Cations vs. Anions Positive ions (lose e-) are called cations. Negative ions (gain e-) are called anions. The charge of an ion is shown in the upper right corner of the symbol.
Ion Symbol Notation Superscript Subscript Mass number Atomic number X +2 Lost 2 e-
So how do you know how many electrons atoms will lose or gain to form an ion?
Ions and the Periodic Table The # associated with the A groups above each representative (main-group) column on the P.T. 1 through 8 gives the number of valence electrons (electrons on the far outside of the atom these e- are the ones used first for chemical bonding!!!) The key to predicting the charge acquired by an element is its position in the periodic table relative to the noble gases. Why noble gases?
Elements that form predictable ions
If an atom has a charge associate with it, it is an ION: 88 Sr 2 38 How many protons, neutrons, and electrons are there? Important: If an atom has a negative charge = an anion. If an atom has a positive charge = a cation.
Practice Problem #1 56 Fe 3 26 Determine the number of protons, neutrons and electrons in this atom. Is this a cation or anion?
Practice Problem #2 32 16 S 2 Determine the number of protons, neutrons and electrons in this atom. Is this a cation or anion?
Practice Problem #3 How many protons, neutrons & electrons are there in the following? a. Cl-38 d. 35 Cl -1 b. Br-80 e. 32 S -2 c. N-14 f. 56 Fe +3