Molecules and Compounds
• Molecule—two or more atoms of the ______ elements combined
chemically
• Compound—two or more atoms of ______ elements combined
chemically
Chemical Reactions
• Atoms are united by _____bonds
• Atoms dissociate from other atoms when chemical bonds are broken
Electrons and Bonding
• Electrons occupy energy levels called electron ________
• Electrons _______to the nucleus are most strongly attracted
• Each shell has distinct properties
• The number of electrons has an upper limit
• Shells _________ to the nucleus fill first
Electrons and Bonding
• Bonding involves interactions between electrons in the outer shell
(valence shell)
• ________valence shells do not form bonds
Inert Elements
• Atoms are stable (inert) when the outermost shell is complete
• How to fill the atom’s shells
• Shell 1 can hold a maximum of ____ electrons
• Shell 2 can hold a maximum of ____ electrons
• Shell 3 can hold a maximum of _____electrons
Inert Elements
• Atoms will gain, lose, or share electrons to _______ their outermost
orbitals and reach a _____ state
• Rule of _______
• Atoms are considered ______ when their outermost orbital has 8
electrons
• The exception to this rule of eights is Shell 1, which can only hold
_____ electrons
Reactive Elements
• Valence shells are not full and are unstable
• Tend to gain, lose, or share electrons
• Allow for bond formation, which produces stable valence
Chemical Bonds
• Ionic bonds
• Atoms become stable through the transfer of electrons
• Form when electrons are completely transferred from one ______
to another
• Ions
• Result from the loss or gain of _______
• _______ are negative due to gain of electron(s)
• _______ are positive due to loss of electron(s)
Chemical Bonds
• Covalent bonds
• Atoms become ______ through shared electrons
• Electrons are shared in ______
• Single ______ bonds share one pair of electrons
• _________ covalent bonds share two pairs of electrons
Covalent Bonds
• Covalent bonds are either ______ or polar
• Nonpolar
• Electrons are shared ______ between the atoms of the molecule
• Electrically neutral as a molecule
Covalent Bonds
• Covalent bonds are either nonpolar or polar
• Polar
• Electrons are ________shared equally between the atoms of the
molecule
• Have a _____ and ______ side or pole
Chemical Bonds
• Hydrogen bonds
• __________ chemical bonds
• Hydrogen is attracted to the ________ portion of polar molecule
• Provides attraction between molecules
Patterns of Chemical Reactions
• Synthesis _______ (A + BAB)
• Atoms or molecules combine
• Energy is ________for bond formation
• Decomposition reaction (ABA + B)
• Molecule is broken down
• Chemical energy is ________
Patterns of Chemical Reactions
• __________ reaction (AB + CAC + B)
• Involves both _________and decomposition reactions
• Switch is made between molecule parts and different molecules
are made