Chemical Bonds

Biological, chemical, and physical properties of matter result from the ability of
atoms to form bonds from electrostatic forces between electrons and protons and
between atoms and molecules. As a basis for understanding this concept:
a. Students know atoms combine to form molecules by sharing electrons to form
covalent or metallic bonds or by exchanging electrons to form ionic bonds.
b. Students know chemical bonds between atoms in molecules such as H2, CH4, NH3,
H2CCH2, N2, Cl2, and many large biological molecules are covalent.
c. Students know salt crystals, such as NaCl, are repeating patterns of positive and
negative ions held together by electrostatic attraction.
d. Students know the atoms and molecules in liquids move in a random pattern
relative to one another because the intermolecular forces are too weak to hold the
atoms or molecules in a solid form.
e. Students know how to draw Lewis dot structures.
f.* Students know how to predict the shape of simple molecules and their polarity
from Lewis dot structures.
g.* Students know how electronegativity and ionization energy relate to bond formation.
h.* Students know how to identify solids and liquids held together by Van der Waals
forces or hydrogen bonding and relate these forces to volatility and boiling/
melting point temperatures.