Nova Science Now-Amazing Atoms-Paint the

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Nova Science Now-Amazing Atoms-Paint the

• http//www.youtube.com/watch?vxqNSQ3OQMGI

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Chapter 1 Section 1 Elements and AtomsWhy are
elements sometimes called the building blocks of
matter?

• All matter (anything that has mass and takes up
  space) is composed of one element or a
  combination of two or more elements

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What is a compound?

• A pure substance made of two or more elements
  that are combined chemically Ex. Sodium Chloride
  (table salt)

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What is a Mixture?

• Two or more substances (elements, compounds, or
  both) that are in the same place but not
  chemically combined

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What is the structure of an atom?

• An atom consists of a nucleus surrounded by one
  or more electrons
• The smallest particle of an element

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How did atomic theory develop and change?

• Atomic theory grew as a series of models that
  developed from experimental evidence. As more
  evidence was collected, the theory and models
  were revised

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What were some of the atomic theories and models?

• Daltons atomic theory atoms could not be
  broken down
• Thomson and smaller parts of atoms an atom that
  consisted of negative charges (electrons)
  scattered throughout a ball of positive charge
• Rutherford and the nucleus An atom was mostly
  empty space. Electrons moved around a small,
  positively charged (protons) nucleus in the
  center of the atom
• Bohrs model Electrons move in certain orbits
• A cloud of electrons Electrons can be anywhere
  outside the nucleus
• The modern atomic model Discovery of the
  neutron

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What is a nucleus and what is inside?

• The nucleus is the tiny, central core of an atom
  that contains protons and neutrons
• Protons Have a positive electric charge ()
• Neutrons Have no charge neutral

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What is the third type of particle that moves
around the nucleus?

• Electrons Very energetic particles that move
  rapidly in all directions electrons carry a
  negative charge (-)

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In an atom, what does the number of protons equal?

• The number of electrons
• Therefore if an atom has 6 protons it would have
  6 electrons to balance the charge

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How do electrons move around the nucleus?

• Electrons move around the nucleus so rapidly it
  is impossible to know where they are at a
  particular time

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Section 2 Atoms, Bonding, and the Periodic Table
How is the reactivity of elements related to
valence electrons in atoms?

• The number of valence electrons in an atom
  determines many properties of that element,
  including the ways in which the atom can bond
  with other atoms

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What are the valence electrons?

• The electrons farthest from the nucleus
• Only these electrons are involved in bonding
• Known as the face of the atom

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How do you show the number of valence electrons?

• An electron dot diagram
• This includes the symbol for an element
  surrounded by dots
• Each dot stands for one valence electron

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What happens when atoms form bonds with each
other?

• Either the number of valance electrons increases
  to a total of 8, or all the valance electrons are
  lost
• Atoms become less reactive chemically stable

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What is a chemical bond?

• A chemical bond is the force of attraction that
  holds two atoms together as a result of the
  rearrangement of electrons between them
• Electrons may be transferred from one atom to
  another, or they may be shared between the atoms
• Reactions occur when bonds are formed or broken

Covalent bond
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What is the atomic number?

• The number of protons in the nucleus of an atom

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How are the elements organized?

• Elements are arranged from left to right and top
  to bottom in order of increasing atomic number
• Remember! The number of protons is the same as
  the number of electrons

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On the periodic table what is a group, or family?

• Elements in the same column, up and down
• Numbers 1-18

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On the periodic table, what is a period?

• A row across the table
• Atomic number increases one at a time as you move
  from left to right across the table

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How do you compare the families of elements?

• Each family has its own characteristic properties
  based on its number of valence electrons
• Noble Gases
• Reactive Nonmetals
• Reactive metals

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What are the Noble Gases?

• Group 18 elements are known as the noble gases,
  or inert (inactive) gases
• All these elements (besides helium, which is
  stable with 2) have 8 valence electrons so they
  dont easily react with other atoms

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What are the reactive nonmetals?

• Group 17, known as the halogen family are very
  reactive
• These elements have 7 valence electrons
  therefore they react easily with other elements
  who atoms can give up electrons

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What are reactive metals?

• Group 1, alkali metal family very reactive
• If alkali metals lose 1 electron they are left
  with zero valence electrons and become more
  chemically stable
• Hydrogen is located above because it only has 1
  valence electron

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What are metalloids?

• Several elements that lie along a zigzag line
  between the metals and nonmetals
• They can behave as either metals or nonmetals

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What does the periodic table tell you about atoms
and the properties of elements?

• As the number of protons (or atomic number)
  increases, the number of electrons also
  increases. As a result, the properties of the
  elements change in a regular way across a period