Those itty bitty particles of matter? Do you remember their name?
The basic building block of all matter?
All matter is made of atoms
If it has mass and occupies space then it is matter and made of atoms
You, the air, your desk, your book, your pencil, your dog, your cat, your food, your teacher, your school, the trees, your house, the dirt, rocks, and even the vacuum cleaner that you are supposed to use to clean your room – but never do!
Just like the letters of the alphabet are the building blocks of words – atoms are the building blocks of matter
Atoms are put together to form different types of matter, just like letters are put together to form different types of words
If the matter is made of the same type of atom, it is called an
If the matter is made of 2 or more kinds of atoms joined chemically, it is called a
Models of Atoms
Since we cannot see an atom, we can use models.
You will notice that each container only has one type of particle, or atom
Some atoms always have a buddy, some are loners.
These containers contain elements
How can you tell?
Models of Compounds
These containers illustrate compounds – 2 or more different atoms, or elements
Atoms aren’t really different colors, but it makes the models easier to understand.
Can you figure out how many different elements are in each container?
Can you figure out what is in each container?
Look closely. Do you see elements, compounds, or both?
There are 90 naturally occurring kinds of atoms. These are called elements
Scientists in the lab have been able to make about 25 more (not naturally occurring)
Is there a list or a chart or a table?
Elements are represented by a symbol of 1 or 2 letters. The 1 st letter is always upper case, the 2 nd is always lower case
Some symbols are easy to remember
Others not so easy
Compounds are represented by 2 or more elements
Which box would represent H 2 O? CO 2 ?
Element or Compound?
How can you tell if a substance is an element or a compound when written in letters?
Count the number of capital letters!
If there is only one – it is an element
If there is more than one – it is a compound
Let’s try some…..
Pb O 2 HCl H 2 SO 4
How do elements become compounds and how do compounds become elements?
Remember: in a chemical change, new substances are formed with different properties.
Scientists have a special way of explaining chemical changes. It is called an
Chemical Equations Are Easy!
The reactants are the elements or compounds you begin with
The products are the elements or compounds you end with
The before and after are separated by an arrow.
Sodium combines with chlorine to produce sodium chloride, or salt
In scientific shorthand it is
Na + Cl NaCl
Your Turn Write a Chemical Equation
Write a chemical equation for each of these. Indicate which are elements and which are compounds.
Hydrogen (H 2 ) reacts chemically with oxygen (O 2 ) to produce water (H 2 O)
When the reactants, carbon (C) and oxygen, undergo a chemical change, carbon dioxide (CO 2 ) is produced
Sugar (C 6 H 12 O 6 ), with the help of oxygen, is broken down by the body to produce carbon dioxide and water.
Your Turn Again! This equation illustrates a chemical reaction or chemical change. Write this equation in words. Indicate what substances reactants, products, elements and compounds.
Elements and compounds can be represented by symbols or formulas
Elements are only one kind of atom, and compounds are one or more elements or kinds of atoms.
Chemical equations are a scientists’ shorthand for explaining a chemical reaction/change.
When matter undergoes a chemical change, new substances are formed with different properties.
Output Page Idea
Like using the letters of the alphabet to make words, can you use the symbols for the elements to make words?