Atoms nucleus protons p neutrons and electrons e

1
Basic Physics and Chemistry

• Atoms nucleus (protons p neutrons) and
  electrons e-
• Chemical elements
• collection of ______with the same number of
  _________ in nucleus
• elements cannot be reduced to simpler chemical
  substances
• elements are unique and have specific chemical
  properties
• Examples hydrogen (H), carbon (C), oxygen (O),
  gold (Au)
• Ions positive () and negative (-)
• The importance of electrons
• oxidation and reduction
• ________________ ( electron clouds)

2

• Important characteristics of the atom
• Atomic Number
• the number of ____________ in the nucleus
• determines the element
• Atomic Mass
• the number of protons neutrons normally
  protons neutrons
• Isotopes
• Atoms of the same chemical element that have a
  different of _________
• Each isotope have a specific number of neutrons
• Some isotopes are _________________

3

• Radioactivity
• Some isotopes have an inherent instability that
  leads to a spontaneous breakdown (radioactive
  decay) of the atom and accompanied by energy
  emission.
• Nuclear bomb radioactive fission (atom
  splitting) uranium and plutonium
• Hydrogen bomb fusion of 2 hydrogen atoms into
  one helium atom the energy of stars
• Nuclear and fusion reactors
• Types of radioactive emissions
• (?? Alpha particles
• energized nucleus of a ____________ atom
  (relatively large particles)
• have low penetration
• (?? Beta particles
• energized ___________ (small particles)
• high penetration
• (?? Gamma rays and X-rays

4

• Radioactive Dating
• Radioactive decay occurs at a constant speed
• it is not affected by temperature, pressure or
  chemicals
• used in atomic clocks to date precisely rocks
  and organic matter
• many types uranium-lead, potassium-argon,
  argon-argon, etc.
• can date materials as old as 4.5 billion years
  (age of Solar System)
• Radiocarbon dating
• Only for __________ matter
• Radioactive isotope C14 decays to C12
• Live organisms maintain same proportion of C14 /
  C12 as in environment
• After death the amount of C14 starts to decrease
  as it decays to C12
• This method can be used only for the past
  ____________ years (history archeology, but not
  _______________)

5
Molecules and Chemical Bonds

• Molecules
• Chemical Bonds
• ionic
• covalent
• hydrogen

6

• Ionic Bonds
• Forms when an atom ________ or ________
  electrons (to fill or empty outer energy levels,
  making it more stable)
• the gained or lost electron interacts with
  another atom to form the ionic bond (example
  NaCl)
• relatively __________
• not directional

7

• Covalent Bonds
• Bond by ______________ a pair of e-
• Shared pair forms a new orbital that envelops
  the nuclei of both atoms
• The _______________ of all chemical bonds
  (involves a lot of energy)
• ________________ (between 2 specific atoms)
• Examples H2, inert gases helium, argon,
  crypton
• Polar covalent bond
• Bond in which the two e- are __________
  unequally this leads to the atoms having either
  a partial positive or partial negative charge
• ____________ bond

8
Hydrogen Bonds

• Attractions between _____________ positive and
  negative charges of atoms
• produce polar molecules (H2O)
• individually very ____________
• highly ________________
• work only in short distances
• combined, are very important for
• water and ice
• structure of macromolecules like DNA and proteins

9
Free Radicals

• Have _____________ e- and thus are highly
  reactive
• Normal product of ________________ using
  _____________
• Examples reactive oxygen - causes a chain
  reaction NO
• Production increased by smoking, alcohol and
  radiation (incl. sunlight)
• Cause mutations, irritate artery walls, aging,
  cancer
• Weapons against them vitamins C and E, beta
  carotene