Chapter 2 – The Chemistry of Life

WATER ATOMS

GOLD ATOMS

Let’s watch…..

What is the diagram hanging in the front of the room? What does it show?

ELEMENTS

A pure substance made of only one kind of atom.

Represented by symbols and organized on a Periodic Table of Elements.

Let’s predict the elements shown.

Periods & Groups

• CALLED PERIODS

• We read the periodic table from left to right.

• Increasing atomic mass from left to right. (the atoms get bigger)

• CALLED GROUPS OR FAMILIES •They share the same reactivity and properties. (like brothers and sisters)

Let’s check out how families are similar!

Alkali Metals

Nobel Gases

METALS NONMETALS

Let’s predict! What elements are found in all living things (Including us)?

Matter

MATTER

ATOMS

PROTONS

NEUTRONS

ELECTRONS

Periodic Table Basics

Warm Up

What are the three subatomic particles that atoms are made of?

(Hint: Look at your notes if you need to)

We will be investigating the first 18 elements since they are the most common to biology.

ProtonsNeutronsElectrons

Make a Model of an Atom

Let’s see what your previous knowledge is!

Working with a partner make a model of an atom using the clay at your desk.

Use the plate as the “nucleus”.

Protons = red (2) Neutrons = purple (2) Electrons = orange (2)

The Atom

Orbital / Energy Level

Electron (-) negative

Nucleus:Protons (+) positiveNeutrons (o) Neutral

Calculating Protons, Electrons and Neutrons

The atomic number gives you the number of _____________of the element.

This number equals the number of ____________.

protons

electrons

Let’s practice!Gold has an atomic number of 79 – How many Protons and Electrons does it have?

79 protons79 electrons

Oxygen has an atomic number of 8 – How many Protons and Electrons does it have?

8 protons8 electrons

Calculating Protons, Electrons and Neutrons

To calculate the neutrons of an elementStep 1: Round the mass number to the

whole numberStep 2: Subtract the atomic number from the mass number

Let’s practice!Helium: Mass Number is: Atomic Number is: Chlorine: Mass Number is: Atomic Number is:

Energy Levels

Also called “orbitals” or “shells”. Electrons are found in the orbitals. Electrons go around the nucleus of

the atom.

2e-

8e-

8e-1

18e-

Nucleus P+

n0

Valence Electrons

The electrons in the last shell or energy level of an atom.

Determine the properties and chemical reactivity of the element and participate in chemical bonding.

Orbital Periodic Table

Let’s look at the first 18 elements on the periodic table. These are the elements most common to biology.

We will color code the subatomic particles and include the orbitals or energy level for each element.

Let’s do one together!

Directions for Energy Level Activity

1. Draw nucleus, shade in & include # of p+ c

2. Draw in the energy levels & electrons (e-)

a. 1st Energy Level = Blueb. 2nd Energy Level = Redc. 3rd Energy Level =

Green

#p+

#p+#n0

Atomic #

Name

Symbol

Nucleus

Orbital 2 8 18

Closure:

Build an accurate model of any element you choose, from 2-18.

Use a plate as the nucleus Use red pom poms as protons Use black pom poms as electrons

Be prepared to explain your model