BASIC CHEMISTRY
Unit 2:
Biochemistry
What are buildings made of?
What are living things made of?
Everything in universe is composed of MATTER
• Matter = anything that has mass and occupies
space
SOLID
LIQUID
GAS
** All matter composed of elements **
• Element = substance that cannot be broken
down chemically into simpler substance
6 elements essential to
living organisms:
• Carbon (C)
• Hydrogen (H)
• Nitrogen (N)
• Oxygen (O)
• Phosphorus (P)
• Sulfur (S)
CHNOPS
Atom = smallest unit of matter
“atmos” – unable to cut
Atoms consist of subatomic particles
Subatomic
particle
Protons
Neutrons
Electrons
Charge
Location
Mass
(Atomic
Mass Unit –
AMU)
Protons & Neutrons
- Protons & neutrons have the same mass = 1 AMU (Atomic Mass Unit)
- 1 AMU = 1.66053886 x 10-24 grams
- Strong forces bind protons & neutrons together to form the nucleus, which is at
“center”
the center
NUCLEUS
- Protons have a positive charge (+)
- Neutrons carry no charge (neutral)
Subatomi
c particle
Charge
Location
Mass
(Atomic
Mass Unit
– AMU)
Protons
+
Nucleus
1
Neutrons
No charge
(neutral)
Nucleus
1
Electrons
NEUTRON
PROTON
Electrons
- Electrons very very very small and have mass of 1/1840 of proton mass = 0 AMU
- Located in shells surrounding nucleus
- Negatively charged (-)
ELECTRON
SHELL
Subatomi
c particle
Charge
Location
Mass
(Atomic
Mass Unit
– AMU)
Protons
+
Nucleus
1
Neutrons
No charge
(neutral)
Nucleus
1
Electrons
-
Shell
0
Atomic number = # of protons
Element Name
(represented by 1 or
2 letter symbol)
Mass number = # of protons + # of neutrons
**Atomic Number (# of protons) determines what element is **
Shells
** Electrons arranged
in SHELLS around the
nucleus **
NUCLEUS
1st SHELL
2nd SHELL
1st shell = 2 electrons
2nd shell = 8 electrons
3rd shell = 8 electrons
15 protons
15 neutrons
15 electrons
3rd SHELL
Draw an example of an Oxygen (O) atom
Draw an example of an Oxygen (O) atom
Atomic number = 8
Mass number = 16
8 protons
8 neutrons
8 electrons
Draw an example of an sulfur (S) atom
Atomic number = 16
Mass number = 32
16 protons
16 neutrons
16 electrons
16 protons
16 neutrons
Isotopes = atoms of same element with different # of neutrons
** isotopes have different mass number (# protons + # neutrons)
-
Nuclei are unstable and break down at a constant rate over time
-
Geologists can determine the ages of rocks and fossils by analyzing the isotopes
found in them
• Compound = 2 or more elements bound together
• Molecule = smallest part of compound that has
properties of the compound
Na
(sodium)
H
(hydrogen)
Cl
NaCl
(chlorine)
(salt)
O
(oxygen)
H2O
(water)
Chemical formula = indicates # of each kind of atom in a molecule
H2O
CH4
H = 2 atoms
O = 1 atom
C= 1 atom
H = 4 atoms
O3
C6H12O6
O = 3 atoms
C= 6 atoms
H = 12 atoms
O = 6 atoms
Chemical Bonds
• Atoms in compounds are held together by chemical
bonds.
• Bond formation involves ELECTRONS
• 3 main types of Chemical bonds
– Ionic = formed when one or more electrons are
transferred from one atom to another
– Covalent bond = formed when electrons are shared
between atoms
– Hydrogen bond = attraction of slightly positive (+)
hydrogen atom to slightly negative (-) atom  weak bond
Ionic Bond = formed when electrons are transferred
from one atom to another
Protons + 11
Electrons – 11
Charge = 0
Protons + 17
Electrons – 17
Charge = 0
Protons + 11
Electrons – 10
Charge = +1
Positive charged
Protons + 17
Electrons – 18
Charge = -1
Negative charged
• Such charged particles called
IONS
Covalent Bond = formed when 2 atoms share electrons
Hydrogen bond = weak attraction of slightly positive hydrogen
atom (+) to slightly negative atom (-) in vicinity
+
+
+
-
+
-
What type of
bond and why?
What type of
bond and why?
What type of bond and why?
Summary of Ionic and Covalent Bonds