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Content objective:

What are we learning and why are we learning this? Content, procedures, or skills.

Vocabulary objective

Tier II: High frequency words used across content areas. Key to understanding directions & relationships, and for making inferences.

Tier III: Low frequency, domain specific terms.

Building on what we already know

Make connections to prior knowledge. This is where we build from.

This intro excerpted from http://www.chem4kids.com/files/atom_intro.html

You are made of different types of atoms.

Atoms are the building blocks of everything in our world.

If you want to create a language, you’ll need an alphabet. If you want to build molecules, you will need atoms of different elements.

Elements are the alphabet in the language of molecules. Each element is a little bit different from the rest.

Why are we talking about elements when this is the section on atoms? Atoms are the general term used to describe pieces of matter.

You have billions of billions of atoms in your body. However, you may only find about 40 elements.

You will find billions of hydrogen (H) atoms, billions of oxygen (O) atoms, and a bunch of others.

All of the atoms are made of the same basic pieces, but they are organized in different ways to make unique elements.

Common Elements

Common elements can build very different molecules.

Books are made of paragraphs. There’s an infinite number of possible paragraphs.

Those paragraphs are made of words – and those words are made of letters.

We only have 26 letters, but we can make tens of thousands of words.

Chemistry works in a similar way. Instead of 26 letters, we have 120 elements.

Letters bond together to form words. Atoms bond together to form molecules.

While the atoms have different masses, they are all built with the same parts.

Electrons, protons, and neutrons combine to make any of the elements.

From Simple to Complex

Small parts combine to form larger structures.

How do the smallest pieces relate to the biggest pieces?

– sub-atomic particles
– Atoms
– Molecules
– Cell organelles
– Cells
– Tissues
– Organs
– Organisms
– Populations
– Ecosystems
– Planets
– Solar systems
– Galaxies
– The Universe

Atoms Are Building Blocks

Atoms are made of electrons, neutrons, and protons.

Atoms are the foundation of chemistry. They are the basis for everything in the Universe.

As you know, matter is composed of atoms. Solids are made of densely packed atoms while gases have atoms that are spread out.

We’re going to cover basics like atomic structure and bonding between atoms.

As you learn more, you can move to the reactions and biochemistry pages and see how atoms form compounds that help the biological world survive.

Are there pieces of matter that are smaller than atoms? Sure there are.

Super-small particles can be found inside the pieces of atoms. These subatomic particles include nucleons and quarks. Nuclear chemists and physicists work together at particle accelerators to discover the presence of these tiny, tiny, tiny pieces of matter. However, science is based on the atom because it is the smallest distinct unit of matter.

Three Easy Pieces

three basic parts of an atom:

electrons, protons, and neutrons.

Electrons have a negative ( – ) charge.

Electrons are found in orbitals that surround the nucleus of an atom.

Protons and neutrons are found in the nucleus.

Protons have a positive ( + ) charge.

Neutrons are neutral – they have no electrical charge!

Atomic mass,weight,number

Atomic weight = # of protons + # of neutrons

Atomic number = # of protons

So what would this mean?

Helium notation


Every element is unique and has an atomic number. That number tells you the number of protons in every atom of the element. The atomic number is also called the proton number.

How much does an atom weigh?

Mass of proton = 1.672 x 10-27 kilograms

Remember negative exponents? That means that the decimal moves to the left.

So this number really means:

00.000000000000000000000000001672 kilograms

That’s a wicked tiny amount.

As you can see from the pic below, neutrons and protons have almost the same mass.

Mass Protones-neutrones-y-electrones
What about the mass of an electron?

It is “something-something” time 10 to the negative 31 kilograms.

How much larger is a proton, as compared to an electron?

Hard way to find out:
Do long division: 1.672 x 10 -27 kilograms / 9.109 x 10 -31 kg =

Easier way to find out:
Use a calculator to do the division: 1.672 x 10 -27 kilograms / 9.109 x 10 -31 kg =

Easiest way to find out: Estimate, using orders of magnitude:

10 – 27 / 10 -31 = 4 orders of magnitude


atomic mass

What is inertia? What is mass?
How is mass related to weight?

Inertia, mass and weight

Also see:

Online textbook chapters to read

Chap 2 Structure of Matter and the Chemical Elements

Chap 11 Modern Atomic Theory & Periodic table

The Element song Tom Lehrer’s song about the periodic table, The Elements!

They Might Be Giants: Meet The Elements Song
They Might Be Giants: Meet the Elements

ACS Middle School Chemistry Lessons

Learning Standards

2016 Massachusetts Science and Technology/Engineering Standards

8.MS-PS1-1  Develop a model to describe that (a) atoms combine in a multitude of ways to produce pure substances which make up all of the living and nonliving things that we encounter, (b) atoms form molecules and compounds that range in size from two to thousands of atoms, and (c) mixtures are composed of different proportions of pure substances.
• Examples could include drawings, 3D ball and stick structures, and computer representations showing different molecules with different types of atoms.

HS-PS1-7. Use mathematical representations and provide experimental evidence to support the claim that atoms, and therefore mass, are conserved during a chemical reaction…. Mathematical representations include balanced chemical equations that represent the laws of conservation of mass and constant composition (definite proportions), and mass-to-mass stoichiometry.

College Board Standards for College Success

Objective C.1.3 Bonding: Students understand that matter is composed of atoms of elements, most of which are bonded in different but predictable ways.

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