the periodic table - chemistry in earth's...
TRANSCRIPT
The Periodic Table
The Periodic TableElements
Periodic Table of Elements
Part I: PTDiscovery of Elements
• Science has come along way since Aristotle’s theory of Air, Water, Fire, and Earth.
• Scientists have identified 90 naturally occurring elements, and created about 28 others(synthetic).
The most abundant element in the earth’s crust is oxygen.
Periodic LawElements( in periodic table) are arranged in order of increasing atomic number they display a regular and repeating pattern of chemical properties and physical properties.
Dmitri Mendeleev Father of The Periodic Table
HOW HIS WORKED…
• Put elements in rows by increasing atomic weight.
• Put elements in columns by the way they reacted.
SOME PROBLEMS…• He left blank spaces for
what he said were undiscovered elements. (Turned out he was right!)
• He broke the pattern of increasing atomic weight to keep similar reacting elements together.
The Current Periodic TableMendeleev wasn’t too far off.Now the elements are put in rows by increasing
ATOMIC NUMBER!!The horizontal rows are called periods and are labeled from 1 to 7.The vertical columns are called (families) groups are labeled from 1 to 18.
Families (Groups) • Columns of elements are called
groups or families. • Elements in each family have
similar but not identical properties.
• All elements in a family have the same number of valence electrons.
Periods• Each horizontal row of elements is called a
period.• The elements in a period are not alike in
properties.• The properties change greatly across even
given row.• The first element in a period is always an
extremely active solid. The last element in a period, is always an inactive gas.
Vocabulary used to explain metals.Malleable = can be pounded into thin sheets
Ductile = can be drawn out into a thin wire
Lustrous: Shiny Brittle: hard but easy to break.
Hydrogen • Hydrogen belongs to a family of its own.
• Hydrogen is a diatomic ( H2,) reactive gas.
• Hydrogen was involved in the explosion of the Hindenberg.
• Hydrogen is promising as an alternative fuel source for automobiles
• Hydrogen bomb
Alkali Metals
• 1st column on the periodic table (Group 1) not including hydrogen.
• Most reactive metals, always combined with something else in nature (like in salt).
• Soft enough to cut with a butter knife
• They react violently with water.
Alkali Earth Metals• Second column on the
periodic table. (Group 2)• Reactive metals that are
always combined with nonmetals in nature.
• Several of these elements are important mineral nutrients(such as Mg and Ca)
Transition Metals
• Elements in groups 3-12• Less reactive harder metals• Includes metals used in
jewelry and construction.
Other Metals● Solid.● Ductile &
malleable.● Conductors of
electricity & heat.
● Have relatively high density.
● Opaque.
Metalloids “The Ladder”
Properties between metals and nonmetals
Able to lose or gain electronsEx: Si appears lustrous, is brittle, not malleable or ductile. Poor conductor of heat and electricity than metals.
Useful in the semiconductor industry.
Halogens• Elements in group 17
Very reactive, volatile, diatomic, nonmetals
• Always found combined with other element in nature .
• Used as disinfectants and to strengthen teeth.
The Noble Gases
• Elements in group 18• VERY unreactive,
monatomic gases• Used in lighted
“neon” signs• Used in blimps to fix
the Hindenburg problem.
• Have a full valence shell.
Lanthanide and Actinide series.• The 30 rare earth
elements are composed of the lanthanide and actinide series.
• One element of the lanthanide series and most of the elements in the actinide series are called trans-uranium, which means synthetic or man-made.
There are 7 Diatoms● Diatomic elements: Inpairs by
nature. TWINS!!!(HOClBrIFN = Huckleberry Finn!)
▪ H2(g) N2(g) O2(g) F2(g) Cl2(g) Br2(l) I2(l)
▪ (volatile in liquid form - evaporates readily)
Diatoms
What does it mean to be reactive?Ex:
What does it mean to be reactive?OCTET & DUET RULE
– All atoms (except hydrogen) want to have 8 electrons in their very outermost energy level (OCTET RULE.)
– Hydrogen want to have 2 electrons in its outermost energy level( DUET RULE)
– Atoms bond until this energy level is complete. Atoms with few valence electrons lose them during bonding. Atoms with 6, 7, or 8 valence electrons gain electrons during bonding.
Charged AtomsCATION:(+)Positively charged atom.ANION:(-)Negatively charged atom.
Part II: Periodic Trends
Periodic trends, shows the arrangement of the periodic table, provide tools to quickly predict an element's properties.
Major periodic trends include:• Atomic Radius• Electronegativity, • Ionization energy, • Electron affinity,
Atomic Radii(Radius)Increase
down group
Decrease across period
ElectronegativityType of MeasureAbility of an atom
to attract electrons– Dec. down
group (electron shielding)
– Inc. across period
Ionization Energy
Amount of energy needed to remove an electron– Inc. across
period– Dec. down group
(electron shielding)
Electron Affinity
Amount of energy released when an electron is added to a neutral atom.
Periodic Trends Review1. Rank the following elements by increasing atomic radius:
C, Al, O, K.2. Rank the following elements by increasing electronegativity: S, O,
Ne, Al.3. What is the difference between electron affinity and ionization
energy?
4. Why does fluorine have a higher ionization energy than iodine? 5. Why do elements in the same family generally have similar
properties?
O, C, Al, K
Al, S,O,Ne
EA. Ability to attract electrons and I.E.energy to remove an electron.
Fluorine is located above the Iodine in the column.
They have the number of valence electrons in their outermost shell.
Matter(Additional notes on matter)• All matter is composed of atoms(elements) and
groups of atoms bonded together, called molecules.– Substances that are made from one type of atom only are
called pure substances. Can not be separated chemically or physically.
– Substances that are made from more than one or more than one type of atom bonded together are called compounds. Can be separated by chemical means only.
– Compounds that are combined physically, but not chemically, are called mixtures. Can be separated.
– Mixtures can be homogeneous(uniformed) or heterogeneous(not uniformed)
Elements, Compounds, Mixtures
• Sodium(Na+) an element.• Chlorine (Cl-) is an element.• When sodium and chlorine bond they make the
compound sodium chloride(NaCl), commonly known as table salt.
Salt is a compound.
Ocean is a mixture