Chem 101 Unit 2

Chemical Bonding and Molecular Geometry

What is an ionic bond?

electrostatic attraction between cations and anions, formed by electron transfer from a metal to non-metal

What is a covalent bond?

mutual attraction of atoms for a shared pair of electrons

What subshells comprise valence electrons?

S and P, d and f are not

Describe metallic bonding?

electrons are shared throughout the lattice of close-packed metal atoms

What special type of structure is found in ionic compounds?

lattice structure

What is a polar covalent bond?

one atom attracts bonding electrons more than the other due to electronegativity, greater difference = more polar

Describe electronegativity as it relates to the periodic table

increases moving L-R and upwards

What is a dipole moment?

measurement of polarity of a molecule

What is the electronegativity difference for an ionic bond?

>2

What is the electronegativity difference for a polar covalent bond?

0.5-2

What is the electronegativity difference for a non polar bond?

<0.5

Name 5 rules for creating a lewis structure

1 find sum of all valence electrons, 2 make central atom the less electronegative one, 3 fill octets of outer atoms 4 fill octet of central 5 if run out of electrons before full octet, put negative charge on most electronegative atom and make fewest absolute number of charges

What exceptions are there to the octect rule?

atom with odd # of electrons, those with less than an octet, those with expanded octet (third period and beyond)

What are resonance structures?

multiple valid lewis structures for one atom

How is the strength of a bond measured?

bond enthalpy, the energy it takes to break a bond, endothermic

What makes an ionic bond stable?

electrostatic attraction

What is lattice energy?