8th-Atomic Structure and Simple Molecules

Introduction to Atomic
Composition and Simple

Molecules

Lesson 1

Lesson 1 Objectives

S.8.11 Develop models to describe the atomic composition of simple
molecules and basic extended structures.

Students will understand what atoms are and the basic structure of
elements.

Students will learn how to read and write chemical symbols and
understand atomic numbers and mass numbers.

Students will understand what molecules are and how they are formed.

Students will learn about ionic and covalent bonds.

Word Cloud

WHAT 1-2 WORDS COME TO MIND WHEN YOU HEAR "ATOM" AND "PERIODIC TABLE"?

Introduction to Atoms &
Elements

●Imagine everything you can touch, see,
and feel is made up of tiny particles
called atoms. Atoms are the smallest
units of matter that still retain the
properties of an element.

The Structure of an Atom:

●Atoms consist of a nucleus made of protons (positively charged)and neutrons (no charge), surrounded by a cloud of electrons (negatively
charged).

Introduction to Atoms & Elements

●An element is a pure substance
that cannot be broken down into
simpler substances by chemical
means.

●Each element made up of only one type of atom.

●The Periodic Table of Elements is
an organized chart with all of the
known elements.

●Some familiar elements include
Hydrogen (H), Oxygen (O), Carbon
(C), and Gold (Au).

●Why do you think understanding
elements is important in science and
our daily lives?

Multiple Choice

An element can have two different types of atoms.

• True

• False

Chemical Symbols in the
Periodic Table

●A chemical symbol is a one or two-letter
abbreviation for an element, derived from
its English or Latin name.

●For example, Hydrogen is represented as
"H" and Gold as "Au".

How is the Periodic Table organized?

●Elements are arranged by increasing
atomic number (number of protons).

●Rows are called periods and columns
are called groups.

Multiple Choice

What is the atomic number of the element Oxygen?

• 6
• 8
• 10
• 12

Chemical Symbols in the
Periodic Table

Why are atomic numbers and mass
numbers important?

●The atomic number tells us the
number of protons in an atom's
nucleus.

●The mass number/atomic mass
is the sum of protons and
neutrons, indicating the atom's
mass.

●Can you find the atomic
number and mass number
for Carbon (C) on the
Periodic Table? What about
Oxygen (O) ?

Word Cloud

Write 1-2 vocabulary words we have learned so far!

Atomic Number- 8

Atomic Mass/ Mass Number- 16
(greater than or equal to .5 always
round up!)

●What if I asked you how many
protons does Magnesium (Mg) have
in its nucleus?
○12, BECAUSE ….the atomic
number is the number of
protons in the nucleus in an
atom of Mg

​

Multiple Choice

How many protons does Magnesium have in its nucleus??

• 10
• 8
• 14
• 12

Introduction to Molecules

●Molecules are groups of two or
more atoms held together by
chemical bonds

Examples:

●1. Water (H2O) - made of 2
hydrogen atoms and 1 oxygen
atom

●2. Carbon dioxide (CO2) - made of
1 carbon atom and 2 oxygen
atoms

●Molecules can be simple (like
H2O) or complex (like proteins in
your body).

Draw

Draw an atom of Lithium- Li,(remember, protons and neutrons are in the nucleus, and electrons orbit around the nucleus)

How Molecules Form: Chemical Bonds

●Molecules form when atoms join together through chemical bonds

Two main types of chemical bonds:

●1. Ionic bonds

●2. Covalent bonds

●The type of bond depends on the atoms involved!

Ionic vs. Covalent Bonds

Ionic bonds:

●Form between a metal and a non-metal

●Involve the transfer of electrons

●Example: Table salt (NaCl)

Covalent bonds:

●Form between non-metal atoms

●Involve the sharing of electrons

●Example: Water (H2O)

Which type of bond do you think is stronger? Why?

Open Ended

Take a guess.....Which bond do you think is stronger, and why? (ionic or covalent)

Draw

Draw a water molecule.