Download Topic 01 Notes - Basic Chemistry

Topic 1
Basic Chemistry
I. Atomic
Theory
of
Matter
 A. Atoms, Elements, and Compounds
 1. atoms – the basic building blocks of matter – cannot
be subdivided by ordinary chemical means
 2. elements – substances made of only one kind of
atom – ex. oxygen, nitrogen
 3. compounds – substance that contains two or more
kinds of atoms in definite proportions – ex. water, salt
 B. Structure of atoms
 1. nucleus – contains two types of subatomic particles
– protons and neutrons
 a. proton – positively charged – the number of protons
determines the atomic number – the number of protons is
equal to the number of electrons in an atom that has no charge
 b. neutron – neutral (no charge) – the number of protons plus
the number of neutrons is called the mass number
 2. shells – electrons are found outside of the nucleus
 electrons have a negative charge and very little mass
 you will find two electrons in the first energy shell and eight
in each shell after that
 not all the shells will be complete – if an atom has eight
electrons in its outer shell it is said to be stable and is resistant
to join with other atoms
 C. Isotopes – same element but with different
numbers of neutrons – atomic number stays the
same but mass numbers are different – many
isotopes are radioactive
II. Chemical bonding and
chemical
reactions
 A. Bonds – the formation of a compound involves either
the transfer or sharing of electrons between atoms – this
results in the formation of bonds – there are three types
that we will focus on
 1. ionic bonds – transfer of electrons – one atom
becomes positive and the other becomes negative
(ions)
Ionic bonds – transfer of
electrons
 2. covalent bonds – sharing of electrons – sometimes
the sharing of electrons is not equal and the covalent
bond becomes known as polar covalent – one atom
will become slightly negative and the other atom will
become slightly positive
Covalent bonds – share electrons –
water is polar and methane is
nonpolar
Polar covalent bonds – electrons
are not shared equally

3. hydrogen bonds - form when a hydrogen atom that is
already covalently bonded to a strongly electronegative atom is
attracted to another strongly electronegative atom
Hydrogen bonds
 B. The strength of the force of attraction:
 1. strongest – ionic bonds
 2. second strongest – polar covalent bonds
 3. third strongest – covalent bonds
 4. weakest – hydrogen bonds
 C. Chemical formulas – shows which elements are
found in a compound – two types
 1. molecular formula – shows how many of each kind
of atom are present in a molecule of a compound
 C6H12O6

2. structural formula –
shows how the atoms of
a molecule are bonded
together
 D. Chemical Reactions – a chemical equation
represents the results of a chemical reaction –
matter is neither created nor destroyed – the
reactants are on the left side of the equation and the
products on the right side of the equation