Name ______Period ______
6-1 Development of the Periodic Table
A)The early periodic table
1)By the end of the 1700’s scientists had identified only 30 elements
2)By the mid 1800’s about 65 elements had been identified using spectra photography andline spectra
3)Their where so many individual elements with slightly different chemical and physical properties that it became hard to keep track of all of them.
4)Chemists began to need a organizationsystem to help keep tack of all these similar but slightly different elements
a)This organization system would ideally group the elements in a way that described therechemical and physicalproperties
B)Dmitri Mendeleev and the first periodic table
1)Dmitri Mendeleev –Organized the 1stperiodic table according to increasing atomic mass
a)Mendeleev put elements with similarchemical and physical propertiesin the samevertical column.
b)Group- a vertical column of elements on Mendeleev periodic table that have similar chemical and physical properties
2)Mendeleev noticed that when elements where arranged according to atomic mass some elements don’t fit into the predicted group. Because of this Mendeleev arranged some elements out of order and put them in the group that best matched their chemical properties.
3)He also left threeempty spaces in his table and used his groups to correctly predictedthe properties of these 3 unidentified elements.
C)Moseley and the periodic law
1)Moseley reorganized Mendeleev’s periodic table the periodic table by atomic number instead of atomic mass
2)When the periodic table was reorganized in this way it was found that all the elements fell into the correct group without the need to reorganize
3)The Periodic Law -When elements are arranged in order of increasing atomic number, their physical and chemical properties show a predictable pattern.
6-2 Reading the Periodic Table
A)What is the periodic table of the elements?
1)The periodic table of the elements is a chart that lists all the elements that have ever existed in a meaningfulway.
2)The elements square on the table contains information unique to that element like atomicnumber, atomic symbol, name of the element and averageatomicmass of the element
3)The location of the elements square on the periodic table tells how that element relates to other elements in terms of its chemical and physical properties
a)Roughly speaking elements the closer two elements are to each other the moresimilar their chemical and physical properties
The elements square on the table contains information unique to that element:B)How are elements squares organized on the periodic table?
1)Groups or Families – The verticalcolumnson the periodic table
a)Elements in the same groups have similar chemical properties because these elements have the same number of valance electrons which are the electrons involved in bonding
b)Because groups or families have similar chemical properties some have been given special names
(I)Alkali metals – elements in group 1 of the periodic table that react with water to make alkaline (basic solutions)
(II)Alkaline earth metals -Elements in group 2 of the periodic table that react with water to make alkaline (basic solutions) and are common in the earths crust
(III)Halogens –Elements in group 7 of the periodic table that react with most metals to produce salt
(i)Halogen is Greek for “salt maker”
(IV)Nobel gas – Elements in group 8 of the periodic table that have a filled valance shell and so they don’t react with any element
(i)Like nobility they don’t mix with any of the “common” elements
Elements in the same groups have similar chemical properties because these elements have the same number of valance electronsFull
1e / 2e / 3e / 4e / 5e / 6e / 7e / Valance
shell
Group names of elements
Alkali
Alkali / Earth / Carbon / Nitrogen / Oxygen / Halogens / Nobel
Metals / Metals / Transition Metals / Family / Family / Family / Gases
C)Are there different types of elements?
1)An element can be classified as one of three basic types, Metals, Nonmetals, and Metalloids or Semimetals
2)In general metals occupy the left side of the periodic table, nonmetals are on the right side of the periodic table, and metalloids separate them in a “magical stairway shape”
The periodic table separates elements into regions of metals non metals and metalloids3)Metals:
a)Physical properties of metals:
(I)Luster- metals are shiny, they reflect light
(II)Metals are good conductors of heat and electricity
(III)Metals have a high density (metals are heavy for their volume)
(IV)Metals have a high melting point
(V)Malleable -metals can be shaped or formed by hammering or pressure
b)Chemical Properties of Metals:
(I)Metals Easily lose electrons in chemical reactions
(II)Metals corrode easily (Example: silver tarnishing and iron rusting)
4)Nonmetals:
a)Physical properties of nonmetals:
(I)Nonmetals have no luster or a dull appearance
(II)Nonmetals are poor conductor of heat and electricity
(III)Nonmetals have a low density (light for their volume)
(IV)Nonmetals have a low melting point
(V)Nonmetals are brittle (they break or shatter easily)
b)Chemical Properties of Nonmetals:
(I)Nonmetals tend togain electronsin chemical reactions
(II)Nonmetals tend not to corrode
5)Metalloids:
a)Physical Properties of Metalloids:
(I)Metalloids can be shiny or dull
(II)Metalloids conduct heat and electricity better than nonmetals but not as well as metals
(III)Metalloids can be dense or light weight
(IV)Metalloids have a melting point between metals and non metals
(V)Metalloids can be malleable or brittle
6-3 Trends in the Periodic Table
A)What can the periodic table tell us about an elements physical and chemical characteristics?
1)As you scan from left to right on the periodic table numerous physical and chemical characteristics become described in trends
a)There are 5 main atomic trends described by the periodic table:
(I)Atomic radius
(II)Ionization energy (successive ionization energies)
(III)Electronegativity
B)How does the periodic table describe an elements atomic radius?
1)Atomic radius -The distance from the nucleus of an atom and its valance electrons
a)This is a very important trend because as electrons get farther and farther away from the nucleus of an atom the atom has a harder time holding on to them
(I)Therefore, in general the larger the atomic radius the more reactive an element is
b)Atoms get largergoing down a group and smallergoing across a period.
(I)Atoms get larger moving down a period because electrons are being added to energy levels farther from the nucleus of an atom
(II)Atoms get smaller moving across a period because the electrons are adding to the same energy level
Atomic Radius Trends on the Periodic TableDistance of electrons from the nucleus matters a lot more in atomic radius than does number of protons and electrons. Just think of what happens when you take two oppositely charged magnets and slowly bring them together (as the distance between the magnets decreases their attraction goes way up). As you move across a period electrons are added to the same energy level (same distance away from the nucleus) and so the additional electrons are just attracted more by the increasing number of protons in the nucleus. As you go down a group on the periodic table electrons are added to energy levels farther away from the nucleus and so the nucleus has less ability to attract them and the radius gets larger.
C)How does the periodic table describe oxidation and reduction?
1)Oxidation – The process of loosing electrons
2)Reduction – The process of gaining electrons
3)The octet rule - An atom will tend to bond, gaining or loosing electrons in order to acquire a full set of valence electrons(noble gas electron configuration).
a)Metals tend to oxidize or loose electrons to obtain their noble gas electron configuration
b)Nonmetals tend to reduce or gain electrons to obtain their noble gas electron configuration
c)Since most of the most common and stable elements involved in life occur in period 2 of the periodic table, a “full valance shell” means 8 electrons
(I)In reality this is the only period of the periodic table that has 8 electrons in its valance shell so it should really be called the octet anomaly
(II)“Octet” = 8electrons = s2p6valance electron shell configuration
Trends for Oxidation and Reduction on the Periodic TableLoose / Loose / Loose / Gain / Gain / Gain
1e- / 2e- / 3e- / 3e- / 2e- / 1e-
Transition Metals Don’t Apply / Depends / Noble Gas
+1 / +2 / +3 / -3 / -2 / -1
Charge / Charge / Charge / Charge / Charge / Charge
D)How does the periodic table describe Ionization Energy?
1)Ionization energy -The energy need to removeoneelectron from an atom.
a)Elements that do not want to lose their electrons (non metals) have highionizationenergies.
b)Elements that easilylose their electrons (metals) have lowionizationenergies.
2)Ionization energy decreases as you move down a group because the elements electrons farther away from the nucleus and thus not being held onto as tight.
3)Ionization energy increases as you moveacross a period because the elements electrons are closer to the nucleus and thus held onto more tightly
a)The trend for ionization energy is opposite that of atomic radius
b)This isn’t a pure trend because atoms with completely filled orbitals tend to hold onto electrons slightly tighter those with incompletely filled orbitals
4)Successive Ionization Energies –Energy required remove electrons beyond the 1st electron.
a)Ionization energies will increase for everyelectronremoved, because the atom becomes more and more positive and thus can hold onto its electrons more and more tightly
Ionization Energy Trends on the Periodic TableIn general ionization energy increases moving across a period and decreases moving down a group
More specifically, atoms with completely filled or evenly filled orbitals are more stable and it therefore takes more energy to remove their electrons than other atoms. (This part is an just for your information, just know the general trend)
E)What is electronegativity?
1)Electronegativity -Reflects an atom’s ability to gainelectrons in a chemical bond.
a)Since non metals tend to reduce, they tend to be moreelectronegative
b)Since metals tend to oxidize they tend to be less electronegative
c)Electronegativity of an element is rated on a scale from 0 to 4, the higher the number the moreelectronegative the element tends to be (the more it wants an electron to fill its outer shell)
d)Electronegativitydecreases as you godowna group, because the atoms radius is so large that the nucleus cant get close enough to electrons to attract them effectively
e)Electronegativityincreases moving across a period, because the atoms radius becomes smaller and therefore can effectively attract electrons
(I)The trend for electronegativity is opposite that of atomic radius
Electronegativity Trends on the Periodic TableMisuro Chemistry 5.0
Unit 6 – The Periodic Table
Page 1 of 9