The Chemistry of Living Cells

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The Chemistry of Living Cells
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What are ATOMS?

• Atoms are the basic building blocks of matter
  that make up everyday objects. A desk, the air,
  even you are made up of atoms!

• There are 90 naturally occurring kinds of atoms.
  Scientists in labs have been able to make about
  25 more.

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Everything is composed of ATOMS!
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Atoms are made of?

• Three basic particles
• Electrons-carry a negative charge, are outside
  nucleus (in a neutral atom, same as of
  protons)
• Protons-carry a positive charge, are inside
  nucleus
• (in a neutral atom, same as of electrons)
• Neutrons-carry NO charge, are inside nucleus
• Ions atoms (or molecules)
• with missing or extra electrons,
• giving it an electrical charge
• ( or -)

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Draw this diagram and label the parts
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Atoms Contain Energy!

• It takes energy to prevent the (-) electrons from
  crashing into the () protons. WHY?

• Electrons are organized in an electron cloud in
  different energy levels.
• The farther away from the nucleus the energy
  levels is, the higher the energy.

The electron cloud shows the most probable
location of the electrons. More to come in
Chemistry!!!
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Energy Levels
This will get more complicated in chemistry!!!)

• VALENCE ELECTRONS
• The electrons in the outermost energy level.
• The maximum number is 8. These are the electrons
  involved in chemical bonding.
• The energy level can have less than the maximum
  but then it is UNSTABLE/UNHAPPY.
• The atom will GAIN or LOSE electrons to become
  stable add (OR IT MAY SHARE!!!!)

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Periodic Table Represents atoms that make up
elements

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Elements

• ELEMENTS Pure substances that consist entirely
  of one type of atom Cannot be broken down into
  simpler substances
• Elements related to living things

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How to read an element on the periodic table?
Atomic of protons and electrons
Atomic mass of protons PLUS
neutrons Protons atomic Electrons same
as protons/atomic Neutrons atomic mass
atomic
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Practice!!

• Hydrogen

• Carbon

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Answers!

• Hydrogen
• Atomic 1
• Atomic mass 1
• Protons 1
• Electrons 1
• Neutrons 0

• Carbon
• Atomic 6
• Atomic mass 12
• Protons 6
• Electrons 6
• Neutrons 6

Extension Draw these atoms above the chart!!!
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Bonds and Compounds

• COMPOUND a group of atoms held together by
  chemical bonds. Example NaCl, H2O

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Chemical Formulas for Compounds

• CHEMICAL FORMULA Shows the number of each
  element in the compound
• ? Each capital letter is a new element
• Subscript ( below the symbol) tells how many
  atoms of that element there are
• If there is not a subscript, it is considered ONE
  atom
• Coefficient in front of the chemical formula,
  tells how many of that compound there are
• Examples C6H12O6 2C6H12O6

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Types of Bonds

• Covalent
• Ionic
• Hydrogen

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COVALENT BONDS Occur when two atoms share a
pair of electrons called molecules, not compounds
MOLECULE a group of atoms held together by
covalent bonds. Example Water
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IONIC BONDS when one or more electrons are
transferred from one atom to another (one loses
electron(s), one gains electron(s)
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Sodium loses an electron-becomes a positive
cation.

• Chlorine gains an electron becomes a negative
  anion.
• The attraction between the cation and anion makes
  the ionic bond.

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• HYDROGEN BOND a weak chemical bond that forms
  between 2 polar molecules.
• POLAR MOLECULES unequal areas of charge.
• Water molecules have a slight () charge at the
  hydrogen and slight (-) charge at the oxygen that
  causes them to attract forming hydrogen bonds.

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Summary of chemical bonds

• Covalent weak (melting sugar)
• Ionic strong (hard to melt salt)
• Hydrogen bonds weakest (individually), but
  strong collectively.