ATOMS AND THE PERIODIC TABLE chapter three

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ATOMS AND THE PERIODIC TABLEchapter three
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ATOMIC THEORY - history
3.1 Atomic Structure
4TH CENTURY B.C. Matter is made of tiny particles called ATOMS.
John DALTON ELEMENTS are made of particles called atoms. ATOMS of the same elements are alike. ATOMS form molecules.
EARLY 1900s (1913) ELECTRONS orbit like planets in the solar system.
MID 1900s (after 1925) Modern theory
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ATOMIC THEORY - STRUCTURE MODEL OF THE ATOM
3.1 Atomic Structure
ELECTRON -
ENERGY LEVELS
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ATOMIC STRUCTURE ELECTRON LOCATION
3.1 Atomic Structure
Electrons are found in energy levels of an
atom. Electrons occupy the lowest energy level
available.
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Energy Levels are like ladder rungs
3.1 Atomic Structure
GAINING ENERGY
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Energy Levels
3.1 Atomic Structure
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ORBITALS where the electrons are located within
an energy level.
3.1 Atomic Structure
S orbital (Like a sphere) may contain up to 2
electrons first energy level is an s orbital
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P orbital
3.1 Atomic Structure

• (Like a dumbbell)
• may contain up to 2 electrons
• second energy level may contain an s orbital and
  up to 3 p orbitals

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Orbitals
3.1 Atomic Structure
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Valence electrons are located in the outermost
energy level of an atom.
3.1 Atomic Structure

• They determine the chemical properties of an
  element.

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3.2 A TOUR OF THE PERIODIC TABLE

• Properties of elements change in a regular
  pattern that the table helps to describe.
• Periods Horizontal Rows
• Groups(families) Vertical Columns

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Traditional Periodic Table
Los Alamos National Laboratory's Chemistry
Division Presents a
Periodic Table of the Elements
3.2 Guided Tour of Periodic Table
 
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The number of protons in an atom determines an
elements location on the table.
3.2 Guided Tour of Periodic Table
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Elements On the Periodic Table
3.2 Guided Tour of Periodic Table
ATOMIC NUMBER
6 C Carbon 12.001
PROTONS (and ELECTRONS too)
SYMBOL
NAME
PROTONS NEUTRONS MASS
MASS
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3.2 Guided Tour of Periodic Table
PROTONS AND NEUTRONS HAVE EQUAL MASS.
ELECTRONS ARE TINY 1800 EQUAL ONE PROTON.
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1
1800
1
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3.2 Guided Tour of Periodic Table

• MASS 35
• ATOMIC NUMBER 17

Cl
protons _?_ electrons _?_ neutrons _?_
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3.2 Guided Tour of Periodic Table

• MASS 35
• ATOMIC NUMBER 17

Cl
protons 17 electrons 17 neutrons 35-17 18
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IONS are atoms that have lost or gained an
electron.
3.2 Guided Tour of Periodic Table

• ELECTRON GAINED
• NEGATIVE CHARGE
• (-)

• ELECTRON LOST
• POSITIVE CHARGE
• ()

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3.2 Guided Tour of Periodic Table
Electron transfer
Na
Cl
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TWO KINDS OF IONS
3.2 Guided Tour of Periodic Table

• A () CHARGED ION IS A Cation.
• A (-) CHARGED ION IS AN Anion.

• EXAMPLES
• LITHIUM
• FLUORIDE

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The atoms of an element always have the same
number of protons.BUT..The atoms of an element
may have different numbers of neutrons.This is
an ISOTOPE!
3.2 Guided Tour of Periodic Table

• Two carbon ISOTOPES
• CARBON 12 6 protons and 6 neutrons
• CARBON 14 6 protons and 8 neutrons

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The AVERAGE MASS of an ATOM
3.2 Guided Tour of Periodic Table

• Why is the mass number not an even number?
• Atoms of the same element exist with different
  numbers of neutrons.
• This makes the mass of different atoms of the
  same element different.
• The average mass is a weighted number so that
  more common isotopes have a greater affect on the
  average than rare isotopes.
• What is an amu?
• It is an atomic mass unit.
• An amu is equivalent to the mass of 1/12 of a
  carbon-12 atom.

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3.3 FAMILIES OF ELEMENTS

• HAVE THE SAME VALENCE NUMBER.
• HAVE SIMILAR CHEMICAL AND PHYSICAL PROPERTIES.
• A COLUMN OF ELEMENTS IS A FAMILY.

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TWO MAJOR DIVISIONS
3.3 Families of Elements

• METALS

• NONMETALS

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GROUP ONEALKALI METALS
3.3 Families of Elements

• VERY REACTIVE
• ONE VALENCE ELECTRON

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GROUP TWOALKALINE EARTH METALS
3.3 Families of Elements

• TWO VALENCE ELECTRONS

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GROUP 3-12TRANSITION METALS
3.3 Families of Elements

• MANY COMMON METALS
• NOT AS REACTIVE AS OTHER METALS

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GROUP 17HALOGENS
3.3 Families of Elements

• VERY REACTIVE
• FORM SALTS WITH ALKALI METALS
• 7 VALANCE ELECTRONS

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GROUP 18NOBLE GASES
3.3 Families of Elements

• INERT / UNREACTIVE
• EIGHT VALENCE ELECTRONS

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SYNTHETIC ELEMENTS
3.3 Families of Elements

• They are man-made and radioactive.
• They include all elements above 92, plus 43 and
  61.

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SEMICONDUCTORS (METALOIDS)
3.3 Families of Elements

• The elements that are between the metals and
  nonmetals are known as
• SEMICONDUCTORS (METALOIDS)
• They may exhibit metallic and nonmetallic
  properties.

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3.4 USING MOLES TO COUNT ATOMS

• Some counting units
• Reams of paper
• Dozens of eggs
• Atomic mass units of protons and neutrons
• Moles of atoms
• A mole is the SI unit that describes the amount
  of a substance.
• Avogadros constant is the number of particles in
  one mole which 6.022 x1023
• molar mass is the mass in grams of one mol of a
  substanceit is equal to the average atomic
  number of an atom.

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Chapter 3Studying for the Test

• Vocabulary
• Parts of an atom
• History
• Element families
• Using the periodic table
• Metal vs. nonmetal