periodic table of elements pages 124-167 ch.4.1, 4.2, 4.3, 4.4 and 5.1
TRANSCRIPT
Dmitri Mendeleev
• He recognized patterns in the element’s approximate atomic masses and their ability to bond with other elements.
http://172.26.64.6/?a=3205&s=00:06:40:24&e=00:07:19:00
Periodic Table
• Based on atomic masses and their ability to bond with other elements, Mendeleev constructed the first periodic Table.
The Atom cont…
• Protons: Have a positive charge.
• The number of protons equals the number of electrons.
Atomic Numbers, Symbols and Mass• Atomic
number is the smaller number and the number of protons in the nucleus.
47
AgSilver
107.868
Element Symbol
Element Name
Atomic mass is all the protons and neutrons added together.
How to calculate # of neutrons
• Atomic mass - Atomic number = # of neutrons
This element is Nitrogen. Its mass is 14. So atomic # of 7, minus atomic mass of 14, equals 7 neutrons.
Count the number of protons. What element is it?
How to Calculate Number of Electrons
• The number of electrons equal the number of protons.
7 electrons
7 protons
• http://172.26.64.6/?a=3205&s=00:07:54:00&e=00:08:13:03
• http://172.26.64.6/?a=3205&s=00:08:24:24&e=00:09:02:00
Valence Electrons
• The electrons on the outermost ring or energy level that can be shared or transferred with other atoms to make compounds.
Valence Electrons and Bonding (ch. 5.1 pgs. 176-182)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.
Without any talking, use your notes and book to answer the following
questions.• What is inside an atom? (pg. 126-127)
• What information does the periodic table tell us? (pg. 132-133)
• What are the columns called? What are the rows called? (pg. 136)
• How do elements relate to each other in rows? What about columns? (pgs. 136)
Groups –Familieselements in a group have verysimilar characteristicsi.e. bonding, reactivity, valence electrons
Periods- elements in a period are not alike, but gradually change as you move from left to right.
• http://172.26.64.6/?a=3205&s=00:09:01:00&e=00:09:55:15
• http://172.26.64.6/?a=3205&s=00:09:55:15&e=00:10:35:11
Properties of Metals• Conductors: Metals are good at conducting electricity.
• Malleable: Ability to bend or pound into shapes.
Properties of Metals cont…
• Reactivity: Ability to react and combine with other elements. Some are more reactive than others. Sodium (Na) and potassium (K) are some of the most reactive metals.
Examples of alloys• Steel: Fe+C+Cr+V• Bronze: Sn+Cu• Brass: Cu+Zn• White Gold: Ag+Au+Zn+Cu
• Yellow gold: Au+Cu+Ni+Zn
ALKALI METALS-Group 1
•So reactive that they are never found isolated in nature, only combined with other elements.
ALKALI METALS-Group 1
Characteristics Properties:
• Soft
• Shiny
• One valance: electron makes them very reactive.
Write down the following:
Reactivity of Hydrogen demo• Purpose: To isolate and observe the
reactivity of an alkali element: H (hydrogen).
• Materials: 250mL flask, mossy zinc, hydrochloric acid, balloon, string, funnel, meter stick, and matches.
• Place enough zinc into the flask to cover the bottom.
• Place the funnel on the mouth of the flask.• Pour enough HCL into the flask to cover the
zinc (about 2cm high)• Quickly, but carefully remove the funnel and
place the balloon over he mouth of the flask.• Let the gas fill the balloon.• Tie the string around the balloon and remove
the balloon from the flask.• Tie the balloon to a safe place.• Attach a match to the end of a meter stick and
light the balloon with the lit match.
Alkaline Earth Metals
• Group 2 metals.
• Very reactive, not as reactive as alkali metals due to having one more valence electron.
• Ca: important for bones.
TRANSITION METALS
• All are good conductors of electricity.
• Fairly stable.
• Fe : Iron is important for carrying oxygen in your blood.
Lanthinides and Actinides
• AKA Rare Earth Elements.
• Placed at the bottom of the table for convenience.
• They are in Periods 6 and 7.
Metalloids
Have some properties of both metals and nonmetals.
They are located on the zigzag line between the metals and the nonmetals.
Physical Properties:
•Can be good at conducting electricity, therefore some are used as computer chips such as Si and Ge.
Non-metals•Non metals lack properties of metals.
•They are on the right side of the periodic table.
•Non metals usually react with metals to make compounds.
•In general, metals give up electrons to non-metals.
Fe
O
Fe2O3 = Iron Oxide = Rust
Predicting Reactions
• Elements become more stable as they gain more valence electrons.
• As a result, atoms will gain, lose or share electrons to form compounds so that they have 8 valence electrons or a full shell.
• This is called the Octet Rule. However there are many exceptions, but this is an easy way to predict common reactions.
Families of Non-metals
• Carbon Family is group 14 and is the only non-metal in that group and is found in all living things.
Families of Non-metals
Nitrogen Family is group 15 and Nitrogen makes up 78% of the earth’s atmosphere.
Families of Non-metals
Oxygen family is group 16 and oxygen makes up approximately 20% of the earth’s atmosphere.
• The Halogen family is group 17. Each element has 7 electrons, therefore it commonly takes one electron away from group one metals to make compounds.
Families of Non-metals
• The Noble Gases are group 18. They have 8 valence electrons, therefore they are very stable and non-reactive.
Families of Non-metals
Hydrogen
• Not a part of group 1.
• Generally found as H2
•It doesn’t fit into any other family because it is so different from all other elements.
The Sun and Nuclear Fusion• How does the sun produce energy?
• During nuclear fusion, two atomic nuclei collide and fuse.
Chemical compositions of Stars:
Each element absorbs different wavelengths of light and shows up as lines on a spectrum.
Star Spectrums• Astronomers can use line spectrums to identify
the chemical elements in a star. Each element produces a characteristic pattern of spectral lines.
The Hertzsprung-Russell Diagram
• Astronomers use H-R diagrams to classify stars and to understand how stars change over time.
The Earth’s Seasons• Equinox: Two days of the year half
way between the solstice, the earth’s axis is neither pointed away or toward the sun. The daylight hours are equal to the nighttime hours.
• Vernal Equinox: or Spring equinox is on March 21st
• Autumnal Equinox: is September 23rd.