Periodic Table and Periodic Trends

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Periodic Table and Periodic Trends
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Activity

• You and partner pull out all the writing utensils
  you have
• Create a method of organizing your writing
  utensils without talking to other groups

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I. Development of Modern Periodic Table

• A. History

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Lavoisier

• Antoine Lavoisier was first to compile list of
  known elements in 1790s

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Mendeleev

• Russian chemist, Mendeleev, organized a table by
  arranging elements in order of increasing atomic
  mass

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• Mendeleev is credited with the first periodic
  table
• Mendeleevs table predicted the existence and
  properties of undiscovered elements

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Moseley

• English chemist, Moseley, discovered that each
  element contained a unique number of protons
• Moseley arranged elements in a table in order of
  increasing atomic number

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Periodic Law

• There is a periodic repetition of chemical and
  physical properties of the elements when
  arranged by increasing atomic number

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B. Modern Periodic Table
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?
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• Periodic Table of the Elements organization of
  elements. Each square shows the name of an
  element, its chemical symbol, atomic number, and
  average atomic mass

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Periodic Table

• elements arranged by increasing atomic number

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Groups

• vertical columns
• also called ______________ or just families
  (well call them groups)

chemical families
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Main Group

• Groups 1,2 through 13-18 are called main group
  elements (A groups )

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Transition Metals

• Groups 3-12 are called transition elements (B
  groups )

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• contains elements with similar chemical
  properties
• EX Li, Na, K

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Periods

• horizontal rows
• physical and chemical properties change somewhat
  regularly across a period
• elements close to each other in the same period
  are more similar than those further apart
• EX K, Ca, Sc

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The Staircase
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• The two sides of the periodic table can be
  divided into metals and non-metals by the
  ____________ line

staircase
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• Non-metals are found to the right of the
  staircase
• all elements to the left of the staircase are
  considered metals (except hydrogen)
• elements that border the staircase are called
  metalloids
• Ex. Si, Ge

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A look into Metals

• What state of matter are most of them in at room
  temperature?
• Do any metals look familiar to you?

Solids (except for Mercury its a liquid)
Silver, Gold, Platinum, Lead, Tin
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Metals

• at the left of the staircase and bottom two rows
• conduct heat and electricity easily
• most are solid at room temperature (Hg is a
  liquid at RT)

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Metals

• exhibit malleability (can be hammered or rolled
  into thin sheets)
• high tensile strength (ability to resist breaking
  when pulled)

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Physical Properties of Metals

• range from soft (sodium) to extremely hard
  (platinum)
• Physical properties of metals include malleable,
  ductile, lustrous, and conductivity of heat and
  electricity
• Malleable can be hammered into thin sheets
• Ductile can be pulled into wires
• Lustrous shiny appearance

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Metals Metalloids Non-Metals
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A look into Non-Metals

• What state of matter are most of them in at room
  temperature?
• Do any non-metals look familiar to you?

Gases But some are liquids and solids too
Oxygen, Hydrogen, Nitrogen
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Non-Metals

• Can be solids, liquids, or gases
• toward right of periodic table
• most are gases at RT

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Non-Metals

• examples of gases nitrogen, oxygen, hydrogen
• examples of solids carbon, phosphorus

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Non-Metals

• solids are typically brittle
• poor conductors of heat and electricity

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Pure carbon
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Metalloids

• along the stair step line that separates metals
  and non-metals
• have some characteristics of metals and some of
  non-metals
• all are solid at room temperature

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Metalloids

• less malleable than metals
• not as brittle as nonmetals
• semiconductors of electricity
• used in electronics

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II. Electrons and the Periodic Table
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A. Valence electrons

• Valence electrons are the electrons in the
  outer-most energy level in an atom
• atoms in same group have similar chemical
  properties because they have the same number of
  valence electrons

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Energy Level Diagrams

• e- p in an atom
• Fills center levels first
• Electrons are dots

8 e- max
8 e- max
8 e- max
2 e- max
Nucleus
Turn to set II of your Study Packet
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Valence Electrons
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Valence Electrons

• the period (row) can indicate the energy level of
  the elements valence electrons
• the Roman numeral for the main group (A group)
  elements indicates the number of valence
  electrons for that group (exception Helium 2
  valence electrons only)

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Valence electrons
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B. Electron blocks

• s-block consists of groups 1(IA) and 2
  (IIA) and the s orbitals are being filled
• p-block consists of groups 13 (IIIA) through 18
  (VIIIA) and the p orbitals are being
  filled
• the d-block consists of groups 3 (IIIB) through
  12 (IIB) and the d orbitals are being filled

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Electron Blocks

• the f-block includes the Lanthanide series and
  the Actinide series and the f orbitals are being
  filled

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S
S
1
P
2
2
3
3
d
4
4
3
5
5
4
6
6
5
7
6
f
4
5
Energy levels
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III. Properties of Elements
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A. Hydrogen

• Group 1/IA and has 1 valence electrons
• Only non-metal in group 1
• has 3 naturally-occurring isotopes

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A. Hydrogen

• can act like a nonmetal and lose an e- or act
  like a metal and gain an e-
• very reactive

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B. Alkali Metals ?link

• Group 1 or IA
• 1 valence electrons
• forms ions with a 1 charge (cations)
• Most reactive metals
• only found combined with other elements in nature

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C. Alkaline Earth Metals

• Group IIA or 2 and all have 2 valence electrons
• forms ions with a 2 charge (cations)
• less reactive than alkali metals, but still
  pretty reactive

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D. Halogens

• Group VIIA or 17 and have 7 valence e-,
• most reactive nonmetals
• only found combined with other elements in nature
• forms ions with 1- charge (anions)

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Halogens are commonly referred to as
Halides(write that down)
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E. Noble Gases (Inert Gases)

• Group VIIIA or 8
• 8 valence electrons, except He that has 2 valence
  e-
• rarely reactive
• most are gases at RT (room temperature)

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Noble Gases

• Examples helium, neon

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F. Transition Metals

• Groups 3 through 12
• fills the d block

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G. Inner Transition Metals

• Also referred to as rare earth metals
• The two rows on the bottom of the periodic table
• Include Lanthanide and Actinide Series
• Fills the f block

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IV. Periodic Trends

• Keep these 3 factors in mind when considering
  periodic trends

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1. Nuclear charge

• Whenever a proton is added to the nucleus, it
  creates a stronger nuclear magnet pulling in
  the electrons even more.

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• Electrons added to the same energy level
  (period) will be pulled in tighter toward the
  nucleus_.
• Ex

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2. Nuclear Shielding

• When an energy level is added to the atom (each
  new period you are adding layers between the
  nucleus and the valence electrons.

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• As energy levels are added, the atom becomes
  larger and you dilute the pull of the nucleus for
  the valence electrons because not only are there
  more layers , but the valence electrons are
  also now farther from the nucleus.

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• (It is easier to remove a valence electron as
  energy levels are added.)
• Ex.

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3. Octet Rule

• Atoms will lose, gain or share electrons so they
  can achieve the electron configuration of the
  closest noble gas.
• As elements get closer to the noble gases on the
  periodic table (further right ), the greater the
  attraction for electrons.

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• Noble gases DO NOT attract electrons
• Elements on the left side of the periodic table
  want to lose electrons, so they will not have a
  great attraction for electrons.
• EX

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A. Atomic Radius

• Atomic radius is defined as one-half the distance
  between nuclei of two like atoms in a diatomic
  molecule
• Ex.

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• measured in picometers (pm), 10-12 m or
  Angstroms (A), 10-10 m
• atomic radius indicates relative size of the atom

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Just the main groups
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1. Group trends.

• Atomic radius generally increase as you move
  down a group. This is mainly due to succeeding
  energy levels being filled.

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2. Period trends

• Atomic radius generally decrease as you move
  across a period from left to right. This is
  mainly due to increasing nuclear charge

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Atomic Radius

• Smallest atomic radius Helium
• Largest atomic radius Francium

Decreases
Increases
increases
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B. Ionic Radius
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B Ionic Radius

• Ionic radius is the measurement of an ion in a
  crystal lattice
• The units of measurements is picometers (pm) or
  Angstrom (Å)

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• 1. Group trends for ionic radii
• Ionic radius increase as you move down a group.
  This is because of the added layers of
  electrons.
• 2. Period Trends for ionic radii
• Ionic radius decrease as you move left to right
  across a period. This is mainly due to the
  nuclear charge.

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Ionic Radius
Decreases
Increases
increases
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C. Ionization Energy

• Ionization energy is defined as the amount of
  energy required to remove an electron from an
  atom.

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1. Group Trends

• Ionization energy decrease as you move down a
  group. This is mainly due to the energy levels.

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2. Period trends

• Ionization energy increases as you move left to
  right across a period. This is mainly due to
  octet

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Ionization Energy

• Smallest Ionization NRG Francium
• Largest Ionization NRG Helium

Increases
Increases
decreases
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D. Electronegativity

• Electronegativity is defined as the tendency for
  atoms of the element to attract electrons when
  they are chemically combined with atoms of
  another element.

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1. Group trends

• Electronegativity decreases as you move down a
  group. This is because the distance from the
  nucleus is increasing

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2. Period Trends

• Electronegativity increases as you move left to
  right across a period. This is mainly due to the
  octet rule.
• Note Noble gases have no electronegativity
  because they dont attract electrons at all.
  Again, think of the octet rule.

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Electronegativity

• Most Electronegative F
• Least Electronegative Fr ( all noble gases,
  of course)

Increases
Increases
Decreases
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Atomic Radius Ionic Radius Ionizing
Energy Electronegativity Nuclear
Charge Shielding
increases
increases
decreases
decreases
increases
increases
decreases
Atomic Radius Ionic Radius Ionizing
Energy Electronegativity Nuclear
Charge Shielding
decreases
increasing
increasing
increasing
decreases