properties of atoms & the periodic table 1 how big is an atom???? (video clip)
TRANSCRIPT
Properties Properties of Atomsof Atoms
& & The The
Periodic Periodic TableTable
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How big is an atom????
(video clip)
Examine the structure of the atom in terms of
1.proton, electron, and neutron locations.
2.atomic mass and atomic number.3.atoms with different numbers of
neutrons (isotopes).
Atomic Structure Goals
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Chemistry
1.1.Determine the trends of the Determine the trends of the followingfollowing:
Number of valence electronsLocation of metals, nonmetals, and metalloidsPhases at room temperature
2. Use the Periodic Table to predict the above properties for representative elements.
Periodic Table Goals
Chemistry
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Matter
Pure Substance
Mixture
Element
Compound
This will be our FOCUS
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Intro Clip
What is an What is an Element?Element?• Elements are the building blocks for
all matter.•One of the ~116 known One of the ~116 known “Pure”, un-cutable “Pure”, un-cutable substances. ….substances. ….that still that still retain the properties of that retain the properties of that substance.substance.
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What is an Atom?•Smallest piece Smallest piece
of matter that of matter that still retains still retains the properties the properties of that matter.of that matter.
•What are they What are they composed of?composed of?
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Subatomic Subatomic ParticlesParticles• Protons• Neutrons• Electrons
NucleusNucleus
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What makes one element different from another element?
Number of protons.
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Rutherford’s Gold Foil experiment led to the discovery of a positive
nucleus.
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ProtonsProtons•Positive ChargePositive Charge•The number of protons determines The number of protons determines
which element it is.which element it is.•All elements have different numbers All elements have different numbers
of protonsof protons•Mass= 1amuMass= 1amu
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•Smallest Smallest subatomic subatomic particle.particle.
•1/1800 the 1/1800 the mass of a mass of a proton.proton.
•Orbit nucleus.Orbit nucleus.•Negative Negative ChargeCharge
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•Electrons Electrons are found in are found in different different levels levels around the around the nucleus.nucleus.
•These are These are called called Energy Energy Levels or Levels or shells.shells.
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Electrons Electrons are found in are found in
the the
Electron Electron CouldCould
SurroundingSurrounding
the nucleus.the nucleus.
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Each Energy Level Can Hold Each Energy Level Can Hold A Certain Numbers of A Certain Numbers of
Electrons!Electrons!Only Only TWO TWO on on the the first first levellevel!!
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Different atoms have different Different atoms have different numbers of electrons!numbers of electrons!
Eight Eight on on the the 22ndnd and and 3rd 3rd levelslevels!!
Each Energy Level Can Hold Each Energy Level Can Hold A Certain Numbers of A Certain Numbers of
Electrons!Electrons!
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Review ClipAdd: Add:
Valence Electrons: Outermost Valence Electrons: Outermost electrons.electrons.
Neutrons• No Charge- Neutral• Found in the
nucleus• Same size as a
protons• Mass= 1amu
• Atomic Atomic NumberNumber
• Number of Number of ProtonsProtons
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1
•Atomic MassAtomic Mass
•Sum of Sum of Protons & Protons & NeutronsNeutrons
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How do you find # of Neutrons???
How can I find out how How can I find out how many electrons an atom many electrons an atom
has?has?•An atom is neutral•So, the number of protons = electrons.
•Atomic number tells you the number of protons.................
•So, it also tells you the number of electrons!
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Review Clip
Practice(on notebook paper)
• Create this chart:Element Symb
ol# of P # of E # of N # of
Valence Electrons
# of Energy levels
Circle Diagrams (Bohr models)
Hydrogen
Carbon
Polonium X X X
Silver X X X
Copper X X X
Calcium X X X
Potassium X X X
Lead X X X
IsotopesIsotopes are atoms that have the same number of protons and differ only in the
number of neutrons.
Most isotopes are stable but radioactive isotopes are unstable and break down into more stable forms by emitting particles and
energy (radiation). Radiation can be detected, so radioactive isotopes are useful as labels in scientific
research and medical diagnostic procedures.
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Isotopes of Carbon
Isotopes of Helium
Still have the same # of protons, so they are still the SAME element.
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Isotope Notation
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Some isotopes are more abundant on earth than others
Electron Dot Diagrams
Shows the number of valence electrons
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1.1.Determine the trends of the Determine the trends of the followingfollowing:
Number of valence electronsTypes of ions formed by representative elementsLocation of metals, nonmetals, and metalloidsPhases at room temperature
2. Use the Periodic Table to predict the above properties for representative elements.
Periodic Table Goals- RevisitedRevisited
Dmitri Ivanovitch MendeléevDmitri Ivanovitch Mendeléev •Grouped elements on the basis of similar chemical properties. •Left blank spaces open to add new elements where he predicted they would occur. •Accepted minor inversions when placing the elements in order of increasing atomic mass. •Predicted properties for undiscovered elements.
Groups or Families
periods
increasing atomic number
•Soft Metals, solids @room temp•Very reactive metals that do not occur freely in nature. •Only one valence electron •malleable, ductile, and are good conductors of heat and electricity.•Cesium and francium are the most reactive elements in this group. •Alkali metals can explode if they are exposed to water.
Alkali Metals Clip
Alkaline Earth Metals Clip
•Two valence electrons•Because of their reactivity, the alkaline metals are not found free in nature.
•All solids at room temp.•Are both ductile and malleable, and conduct electricity and heat. •The interesting thing about transition metals is that their valence electrons change. •There are three noteworthy elements in the transition metals family. -iron, cobalt, and nickel, and they are the only elements known to produce a magnetic field.
Transition Metals Clip
Metalloids•Metalloids have properties of both metals and non-metals. •Some of the metalloids, such as silicon and germanium, are semi-conductors. This means that they can carry an electrical charge under special conditions. This property makes metalloids useful in computers and calculators •All solids at room temperature
Clip
Halogens
•"halogen" means "salt-former" and compounds containing halogens are called "salts". •All have 7 valence electrons.•Form many compounds with the alkali metals. •exist, at room temperature, in all three states of matter:
Solid- Iodine, Astatine Liquid- Bromine Gas- Fluorine, Chlorine
CLIP
Noble Gases•All have 8 valence electrons
•Chemically inert
•All gases at room temp.
•They all have very low boiling and melting points.
•They all put out a color in the visible wavelengths when a low pressure of the gas is put into a tube and a high voltage current is run through the tube. This type of tube is called a neon light whether the tube has neon in it or not.
Clip
•The thirty 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. •All of the rare earth metals are found in group 3 of the periodic table, and the 6th and 7th periods.•All rare earth elements have 3 valence electrons and are solid at room temp.
Rare Earth Metals
Clip
AllotropesSame formula- different structure
•Where are these found on the Periodic table?
•Never found in nature alone.
Br Br I I
Metals vs. NonmetalsMetals vs. Nonmetals
Metallic bonding: e- move freely among a metal’s positive charges ions
• Lose their valence
electrons easily. •Good electrical conductors and
heat conductors. •Malleable &
Ductile•Solid at room temperature
•Gain or share valence electrons
easily.•Poor conductors
of heat and electricity.
•Brittle - if a solid. •Nonductile.
•Solids, liquids or gases @ room
temp.
Electron Donors Electron
Acceptors
Periodic Trends
Atomic Radii
The greater the number of protons present, the stronger the attraction that holds the electrons closer to the nucleus, and the smaller the size of the shells.
