Valence e s of an atom - (total unbonded e s +
total bonded e s)
Molecular structures that tend to be the common one have a formal
charge is closest to zero and any negative charge is on the most
When 2 or more atoms are strongly attached (attracted) to each
These forces act inside an atom or molecule:
Gain/lose e s (strong metal + strong nonmetal)
Share e s (weak metal or nonmeta
H: Energy given off or taken in during a reaction.
H = t> Exothermic
H = +
Breaking bonds requires energy
Forming bonds releases energy
CH + 2O CO + 2H OO
4 (C H) = (4
2 (C=O) = (2
The time it takes
the amount of a substance to decay.
5g of nuclide
How much of the original nuclide remains
The energy needed to remove an e
Bond Lengths of Covalent Bonds
Single - Longest
Double - Medium
Triple - Shortest
Difference in electronegativity determines the character of the bond.
Large difference Ionic Bond
t> Biggest difference is 3.3
Medium difference Polar Cova
Rule of Octet
Atoms tend to bond in such a way as to gain, lose, or share e s in
order to gain a complete valence (outer s and p).
Structures for Atoms
Structures for Ions
Structure for Ions of Molecules
Lewis Structures for Molecular Structures (Covalent)
Add valence e s from all the atoms.
Write the symbols for the atoms. If there are more than 2 atoms,
identify the central atom. Connect them with a single line which
represents 2 shared e
When a positively charged nucleus emits its p leaving only the n .
When an electron in orbit falls into the nucleus (positively charged) and
makes it neutrally charged.
Understanding why are some nuclides are radioactive while others are
t> Try to rip apart the nucleus because of like charges
t> Try to pull together the nucleus because subatomic particle
When a big nucleus ejects a He
size chunk of itself.
When a neutrally charged particle (equal amount of p s and e s)
ejects its e s leaving only the p s.
When a particle experie
A system of electrodes and electrolytes in which chemical reactions produce electrical energy or an
electric current produces chemical change
Features of an Electrochemical Cell:
o Two electrode