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The Periodic Table
Transcript of The Periodic Table
Periodic Table What is the periodic table? Evolution of the Periodic Table Conclusion The periodic table is a table of the chemical elements, showing the symbols for the elements, their full names, their atomic numbers and their mass number and well as many other important features. It organizes a great deal of information about all the known elements We need the periodic table because it is a very convenient way to find information about elements, which allows us to use that information efficiently. Before the Periodic Table… There was no sure way of classifying and organizing the elements that were known by scientists. There was mass confusion and a lot of speculation in the scientific community. Basically, life sucked for chemists. Based on Mendeleev's original idea and modified over the Centuries the Modern day Periodic Table has become one of the most important and crucial tool's in helping us understand chemistry and the universe itself because of it's genious structurization which makes it one of the most utilised thing among scientists. The Atomic number
is the number of protons
found in the nucleus
of the element. The Atomic Mass is the Total Mass of all the Protons, Electrons and Neutrons in a single atom of the element. Why do we need it? 330 BC- Aristotle made the theory of 4 elements that created the planet: water, fire, air, earth 1789- Lavoisier made a list of 33 elements, and distinguished between metals and non-metals 1869- Meyer made a list of 56 elements based on certain properties when ranged in order of atomic mass 1894- Ramsay discovered the Noble Gases 1869- Mendelev made a table based on atomic weights. Gaps were left for elements that were unknown at that time and their properties predicted. Furthermore, in the 1900`s, researchers have found more elements. All these discoveries are what made the periodic table as it is today!
It was another guy, Henry Moseley discovered how to measure an atom’s atomic number.
Now, elements put in rows by increasing atomic number instead of their increasing atomic mass. The horizontal rows are called periods and are labeled from 1 to 7.
The vertical columns are called groups are labeled from 1 to 18. Elements in the same group have similar chemical and physical properties (Mendelev planned this).
they have the same amount of valence electrons,
causes them to form the same kinds of ions
form predictable reactions. Groups are really handy! Hydrogen Hydrogen belongs to a family of its own. Hydrogen is a diatomic, reactive gas. Alkali Metals are in the ________ column on the periodic table not including hydrogen.
Most reactive metals, Always lose their valence electron (cation)
Always combined with something else in nature (like in salt).
Alkali Metals Alkaline Earth Metals Elements in Group 2 have _____ _____________ electrons
which are usually lost in reaction (cations)
Gives them an oxidation state of +2 (lose 2 electrons)
The 38 elements located in groups ___ to ___
Generally less reactive metals
A transition metal may lose 1, 2 or 3 valence electrons depending on the element with which it reacts
Can put more than 8 electrons in their 2nd to last shell
Transition Metals Semimetals or Metalloids Metalloids are the elements found along the staircase
Properties of both metals and non-metals.
Have unusual electrical properties (Semi-conductors) Most reactive group of nonmetal elements.•
When halogens react, they often gain the one electron (just one?)
Which element group would halogens most likely react with? Noble Gases The six noble gases are found in group 18
All noble gases have the maximum number of ________ electrons making them stable and inert Important Terms Atomic Radius Ionization Energy As you proceed from left to right the trend on the periodic table is for the ionization energy to increase. As you proceed down a group the trend is to decrease the atom's ionization energy.
So overall Helium has the greatest ionization energy and Francium has the least! The ionization energy is the exact quantity of energy that it takes to remove the outermost electron from the atom. When enough energy is added to an atom the outermost electron can use that energy to pull away from the nucleus completely, leaving behind a positively charged ion. That is why it's called ionization, one of the things formed in the process is an ion. Lanthanides and Actinides Three quarters of elements are metals
Have metallic Luster, very dense, and only melt at high temperatures.
Malleable and Ductile
Metals will corrode, gradually wearing away, like rusting iron.
Solids at room temperature (except Mg) Metals Non-Metals Nonmetals, on the right side of the periodic table, are VERY different from metals. The Periodic Table http://dl.clackamas.cc.or.us/ch104-07/ionization_energy.htm BIBLIOGRAPHY! http://chemistry.about.com/od/chemistryglossary/a/atomicradiusdef.htm http://www.webelements.com/ http://www.chemicool.com/ Hebden: Chem 11 Text Wikipedia.com Why is it called the "Periodic Table"? Brief History:
Most of the Periodic table we know can be attributed to Russian Chemist
Dmitri Mendeleev People generally like to organize things. The table was designed by Mendeleev in 1869 so that recurring trends in properties of an element could be shown Silicon (Si) is used in making rubbery cookware, and are very good semi-conductors often used in the electrical/computer industry Groups Period 1 2 18 17 16 15 14 13 1 2 3 4 5 6 7 Groups 18 Na A.k.a Rare Earth Metals The Modern Periodic Table contains 118 elements which are classified into 12 categories (families). Your responsible for 6
Families may be one column, or several columns put together. Each family has a specific name. (Just like your family has their own last name.) Lanthanum Neodymium Common, but mixed into rock the world over. Responsible for miniaturizing computers and headphones, powering hybrid cars Distance from the nucleus to the tip of the surrounding cloud of electrons. It ___________ as you go down the group because the energy levels (shells) are increasing.
More energy levels, = further electrons from the nucleus
Result: a larger atomic radius. Inert substances don't react! Their outter shell (valence) is FULL!!! This is why it's "safe" to breathe in Helium and not reactive elements like Chlorine, Lithium etc... Noble Gases: Full Shells Why does the voice change when breathing Helium? Examples Only recently being utilized Most car batteries use lead: Inefficient and heavy Smaller, lighter but more power No, I can't get any of this Halogens It decreases as you go left to right because of the greater amount of protons. Higher the atomic number = more protons.
The protons will pull the electrons closer to its nucleus
Result: in a smaller atomic radius. Atomic Radius Increasing 2) Decreasing 1. How many Valence e- are in each different group? 3. Which groups lose e- easily?
Which gain easily? 4. Why do we place all noble gasses in one column? (ignore transition and rare earth metals) 2. Halogens react the most violently, why do you think that is? Rare Earth Metals Cheat Sheet Lay vs. Scientific Luster
Example: fluorine and chlorine are both gases that irritate your lungs.
Example: copper and silver are both metals that tarnish when exposed to air. RECALL Mendeleev noticed that some elements shared physical and chemical properties. Mendeleev was not too far off. Interesting way to categorize elements... http://education-portal.com/academy/lesson/electronegativity-trends-among-groups-and-periods-of-the-periodic-table.html http://news.cnet.com/8301-13579_3-57520121-37/digging-for-rare-earths-the-mines-where-iphones-are-born/ Who takes the most credit for creating the periodic table we use today in our textbooks? How are elements arranged today in the PT? Difference between a period and group?
Group and a family? Dull and generally good insulators They have low density and low melting point Brittle Solid, liquid or gasses at room temperature The word "alkali" received its name from the Arabic word "al qali," meaning "from ashes". These particular elements were given the name "Alkali" because they react with water to form hydroxide ions, creating a basic solution (pH>7). ("Earth" is derived from its inability to decompose when exposed to heat.) 1. Which of the following is NOT an Alkaline Earth Metal?
(a) Ba (b) K (c) Mg (d) Be (e) Ra
2. True or False: Alkaline Earth Metals do not react vigorously with water.
3. What alkaline metal is a main component in our bones? The transition metals are able to put up to 32 electrons in their second-to-last shell. Something like gold (Au), with an atomic number of 79, has an organization of 2-8-18-32-18-1. Magnets of fMRI Machines Metals are located to the ________ of the staircase and nonmetals are located to the _________ of the staircase. a property of most nonmetals in the solid state is that they are
b) good conductors
d) ductile As you move from right to left and down, metallic characteristics increase Which element has the least metallic character?
d) Si An atom of chlorine and an atom of bromine have the same
a) electron affinity
b) size (radius)
c) favorite color
d) number of valence e- Meet the Family (stuck in the middle)