Atoms and the Periodic Table

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Chapter 17

• Atoms and the Periodic Table

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Basic Definitions

• Chemistry
• is the study of the composition, structure, and
  properties of matter and the changes it undergoes.

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More Intro Stuff

• Chemistry can deal with questions like
• What is this material made of?
• What type of things will this substance react
  with?
• Why is carbon dioxide transformed by plants into
  oxygen?

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17.1

• Atom is the smallest unit of an element that has
  the same properties of that element.
• Element is a pure substance composed of only one
  kind of atom.
• Compound is a substance that is made of two or
  more elements that are chemically bonded together.

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Atoms are old!

• Hydrogen is the oldest and most abundant element
• The atoms in your body existed since the
  beginning of time
• We recycle atoms!

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Atoms Composition

• Protons positive parts in the nucleus
• Neutrons- neutral parts in the nucleus
• Electrons- small negative parts around the
  nucleus
• The movement of electrons is electricity!

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Periodic Table

• Periodic table is a grouping of elements in
  order of increasing atomic number.
• Atomic symbol the letters by which the element
  is designated
• Frequently from the Latin name
• First letter capital, second lowercase (Si)

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17.2

• Atoms are mostly empty space
• Everything around us is mostly empty spacehuh?
• We dont fall into each other because your
  electrons repel my electrons like a magnetwe
  push off before we fall in like a ghost!
• You know you never actually touch someoneWHAT??!

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Craziness Cont. 17.2

• The repelling electrical fields create the
  feeling of touch, but there is always a layer of
  electrons between you and the other person.

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17.3

• Protons are 2000 times larger than electrons, but
  have the same charge
• The number of protons in an atom equals the
  atomic number
• All elements have a different atomic number.
• (elements fingerprint)
• Note In an atom, the number of protons is equal
  to the number of electrons.

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Isotopes

• Isotopes
• atoms of the same element with a different mass
  because of a different number of neutrons.
• The number of neutrons in an atom can change, but
  the proton number will always remain the same.

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Designating Isotopes

• There are two ways to designate isotopes
• Hyphen notation
• is when you write out the element name followed
  by a hyphen and the mass . Calcium 40
• Nuclear notation
• is when the element symbol is written, then in
  the upper left is the mass number. 40Ca

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17.4 (Write this down, practice tomorrow!)

• neutrons protons mass number
• neutrons mass number atomic number

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17.5/17.6 - Periodic Table

• Vertical columns on a periodic table are called
  groups or families. (label your table!)
• Horizontal rows on a periodic table are called
  periods. The periods are numbered Period 1 to 7.

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Metals vs. Nonmetals vs. Metalloids

• Metals
• left side of the periodic table
• good conductors of heat and electricity
• malleable (can be hammered into sheets)
• ductile (rolled into wire)

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Metals vs. Nonmetals vs. Metalloids

• Nonmetals
• right side of the periodic table
• poor conductors of heat and electricity
• gases or brittle solids.
• Metalloids have properties of metals and
  nonmetals.

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Periodic Table

• Across the periodic table the properties of
  elements gradually change periodic trend
• Example atoms get smaller as your move from the
  left to the right
• Down the periodic table the elements properties
  are very similarhence the names group or family

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Periodic Table Families

• Group 1 Alkali Metals
• Group 2 Alkaline Earth Metals
• Group 3-12 Transition Metals
• Group 16 Chalcogens
• Group 17 Halogens
• Group 18 Noble Gases

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• Alkaline Metals
• Middle ages, ash mixed with water.alkaline
  metals
• Alkaline Earth Metals
• Alkaline solutions in water, didnt melt in fire
  earth
• Chalcogens
• ore-forming oxygen and sulfur common in ores
• Halogens
• salt-forming NaCl (table salt)
• Transition Metals
• Lanthanides (inner transition metals)..some used
  in LEDs
• Actinides (inner transition metals)nuclear power
  industry, uranium and plutonium

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Noble Gases

• The Noble Gases are group 18
• very stable
• do not like to react with anything
• Most of the Noble Gases are used in lighting, and
  helium is used to inflate balloons so that they
  float.