All-you-need-to-know
Inorganic Chemistry
for Honors Biology students
(ch. 2)
Chemistry in Biology / Organic Chemistry Unit
Atoms, Elements, and Compounds (2.1 part 1)
Chemistry is the study of matter and how it combines
to form new substances.
Organic and inorganic matter are both made of atoms.
The atoms in organic matter are arranged in larger,
more complex units or “biomolecules.”
Hierarchy / Levels of Organization of Matter in the Biosphere
Chapters 2 &3
Atoms
 biological molecules  Organelles  Cells  Tissue 
Organ  Organ system  Organism 
Population  Community  Ecosystem  Biosphere
Atoms are the inorganic building blocks that
make up organic matter.
Levels of Organization of Matter
in the Biosphere
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
ETC…
Atoms - The Building Blocks of Matter
 Protons are positively charged particles.
 Neutrons are particles that have no charge.
 Electrons are negatively charged particles that are located
outside the nucleus.
 The first shell/orbital of an atom fits 2 electrons; the next two
shells fit 8 electrons.
Comparing the Parts of an Atom
Mass in AMUs (Atomic Mass Units)
Atoms, Elements, and Compounds
Elements
 An element is a pure substance that cannot be broken down
into other substances by physical or chemical means.
 There are over 100 known elements, 92 of which occur
naturally.
 Each element has a unique name and symbol.
 Elements are defined by their atomic number, or number of
protons.
Silver
Aluminum
Gold
Helium
Most Abundant Elements in the Human Body (~70% of body weight is water, H2O!)
Oxygen (O)
(normally a gas,
here a blue liquid; most
abundant in body,
needed to get energy
from food, found in
water and air)
Phosphorus (P)
(found in DNA)
Carbon (C)
(found in all
organic
molecules)
Potassium (K)
Hydrogen (H)
(ionized gas,
In a galaxy,
found in water
and air)
Sulfur (S)
Nitrogen (N)
(normally a gas,
here a liquid, makes
up most of air,
needed for proteins
and DNA)
Sodium (Na)
Calcium (Ca)
(needed for bones,
muscle contraction)
Magnesium (Mg)
(silver color)
Chlorine
(Cl) (gas)
Element song
Abbreviated Periodic Table / Chart
Atomic Number 
Element Symbol 
Atomic Mass 
(a.m.u.)
6
C
12.01
Introduction to the Periodic Table
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The periodic table shows all of the known elements in order of increasing
atomic number.
The periodic table is organized to group elements with similar properties in
vertical columns.
Nonmetals 
(right of “stairs”)
The
elements
we will
use are in
these
areas 
Metals (left of “stairs”)
Atomic Number, Mass Number, Atomic Mass
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Atomic number = no. of protons (p+), identifies the
element
The atom is neutral (net charge = 0), therefore
no. protons = no. electrons
Mass Number = no. of atomic mass units in nucleus
= no. protons + no. neutrons
(1 a.m.u. = mass of one nuclear particle)
Atomic Mass = average mass of all isotopes (different
atoms) of an element in a.m.u.
round the atomic mass  mass number
Isotopes
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Isotopes are atoms of the same element (same number of
protons) that have different numbers of neutrons (and different
mass no.)
Symbol for isotope – element symbol-mass no.: C-12, C-14,
Na-23, Na-24, etc.
Heavy or radioactive isotopes can be used for many
applications in industry, medicine, environmental science,
etc.
In medicine, less common stable and radioactive isotopes,
are used as biological tracers.