Presentation on theme: "Take Out Pencil Annotated article. Catalyst 1.What was Johann Döbereiner’s contribution to chemistry in 1829? 2.Why is Dmitri Mendeleev considered the."— Presentation transcript:
Catalyst 1.What was Johann Döbereiner’s contribution to chemistry in 1829? 2.Why is Dmitri Mendeleev considered the “Father of the Periodic Table”? 3.Why do you think the placement of H and He are considered “unresolved issues”?
Your task in class today, and to finish for class on Tuesday (2 nd & 3 rd periods) or Wednesday (4 th & 5 th periods) is to create a timeline of the history of the periodic table. You may use your reading packet, as well as any other information you find in books and online. The rubric must be attached to the front of your timeline before it will be accepted. Your Period Table Timeline must: Include at least 6 dates/time periods Include a written description of the event next to the date/time period Include a visual representation next to each date/time period Take up almost all space on an 8.5 x 11 sheet of printer paper (you may use a larger piece of paper too) Include a title Include your full heading on the back
Homework Complete your Periodic Table Timeline and bring in to class, with rubric attached to the front If you have colored pencils, please bring them with you to class tomorrow
Take Out Catalyst sheet Pencil Science Notebook Make a pile of timelines in center of table w/ rubric attached Tape paper I give you onto page 48
Catalyst Complete page 48 in science notebook with your group On your Catalyst sheet, describe in detail the patterns that you see on page 48
Why isn’t the world made only of elements? How do the atoms of different elements combine to form molecules? The answers to these questions are related to electrons and their energy levels. And the roadmap to understanding how electrons determine the properties of elements is the periodic table.
Valence Electrons: The key to bonding You have learned that electrons are contained within energy levels. An atom’s valence electrons are those electrons that are in the highest energy level and are held most loosely.
The number of valence electrons in an atom of an element determines many properties of that element, including the ways in which the atom can bond with other atoms.
8 is the lucky number!! Most atoms are more stable – less likely to react – when they have filled their outer most energy level OR if they have eight valence electrons (their outer s & p orbitals are full). In your notes, draw the electron dot diagrams of hydrogen, carbon, and oxygen.
How many more electrons are needed to make an oxygen atom stable? A hydrogen atom? A carbon atom?
A row of elements across the periodic table is called a period. Hydrogen and helium make up the first period. Label the periods. Elements in the same column are called a group or family. Label the groups of your periodic table.
A period ends when the highest energy level has eight electrons. The elements within a group always have the same number of valence electrons, and for this reason, the elements within a group have similar properties.
Why the name “noble gas”? Most atoms are more stable – less likely to react – when they have eight valence electrons. The other elements strive to be like this! They strive to be stable. On your periodic table, color your noble gases orange.
When atoms react they usually do so in a way that makes each atom that is participating in the bond more stable. One of two things may happen: 1.The number of valence electrons increases to eight (or two in the case of hydrogen). 2.The atom gives up its most loosely held valence electron(s).
Atoms that react this way become chemically combined, or bonded together. A chemical bond is the force of attraction that holds two atoms together as a result of the rearrangement of valence electrons between them.
Look at the elements in the column just to the left of the noble gases. The elements in group VIIA are called the halogens. Atoms in the halogen family have seven valence electrons. A gain of just one more electron gives these atoms the stable number of 8 electrons. As a result, elements in the halogen family react easily with other elements whose atoms can give up or share electrons.
When iodine, a halogen, reacts with aluminum, a purple gas is produced Bromine, a halogen, reacts vigorously with hydrogen http://www.youtube.com/watch?v=gFGwY_S4j _M http://www.youtube.com/watch?v =R6bBs2D0cpA
At the far left side of the periodic table is Group IA, called the alkali metal family. Atoms of the alkali metals have only one valence electron. Therefore, alkali atoms can become chemically more stable by losing their one valence electron. This makes them very reactive. Color the alkali metals yellow. http://www.youtube.com/watch?v=fmOd8_Re NnQ
The alkaline earth metals are in Group IIA The alkaline earth metals are silver colored, soft metals, which react readily with halogens to form ionic salts, and with water, though not as rapidly as the alkali metals, to form strong alkaline (basic) hydroxides. Color the alkaline earth metals red
Take Out Catalyst Pencil Science notebook open to Vocabulary
Catalyst Describe everything you know about alkali metals and alkaline earth metals
Catalyst Describe the difference between a metal and non-metal
Other metals polonium Very rare radioactive metal that is used as fuel in nuclear reactors; it emits radiation that is much more powerful than that of uranium. bismuth Relatively rare metal that is used especially in alloys and cosmetics and in medicine (treatments for gastric ulcers and diarrhea). lead Heavy toxic metal that is used to prevent corrosion, as a protection against radiation and in accumulator batteries, paint and glass. thallium Metal that is used especially in infrared detectors and some kinds of glass. tin Metal that is used especially as an anticorrosive for copper and steel and as a component in the preparation of bronze, welding and toothpaste. indium Very rare metal that is used especially in race car engines and electronic devices, and as a coating for glass. gallium Rare metal that is used especially in high-temperature thermometers, electroluminescent diodes and television screens (the color green). aluminum Light metal that is used especially in aeronautics, cars, buildings, electric cables, kitchen utensils and packaging. Color the “Other Metals” brown
What happens when an atom loses or gains electrons? An ion is formed An ion is a charged atom or particle Cation = a positively charged particle (electrons were lost) Anion = a negatively charged particle (electrons were gained)
Several elements, known as metalloids lie along a zigzag line between the metals and the nonmetals. Depending on the conditions, these elements can react as either metals or nonmetals. The metals have from 3 to 6 valence electrons and can either lose or share electrons when they combine with other elements. Color these metalloids blue
The elements below are nonmetals, and have four or more valence electrons. Like the halogens, these nonmetals become stable when they gain or share enough electrons to have a set of eight valence electrons. Color these nonmetals green
Hydrogen Hydrogen is considered to be a nonmetal. It is located above Group 1 in the periodic table because it has only one valence electron. However, even though hydrogen is a reactive element, its properties differ greatly from those of the alkali metals. http://www.youtube.com/watch?v=fesgl5Cs5FY
Freefall http://www.youtube.com/watch?v=dOoHArAzd ug
Homework Update Vocabulary Study all Vocab and Periodic Table Notes for Quiz on Monday