Atoms
What is the smallest unit of an element that still has the properties of that element?
Atom
What is matter?
Anything that has mass and takes up space.
What is a compound?
A substance made of two or more different elements that are chemically joined.
What is a mixture?
Two or more substances physically combined.
What happens to atoms during a chemical reaction?
They are rearranged.
What are the three main parts of an atom?
Proton, Neutron & Electron
What is a substance?
A type of matter that has specific properties and is made of one kind of particle.
Is O₂ a compound? Explain why or why not.
No. O₂ is a molecule, but it is not a compound because it contains only one element.
Are the substances in a mixture chemically joined?
No
What are the substances you start with in a chemical reaction called?
Reactants
Which part of an atom has a positive charge?
Proton
How can you tell two substances apart?
By comparing their properties.
Is H₂O a molecule, a compound, or both?
Both
Can the substances in a mixture be separated?
Yes. The substances in a mixture can be separated using physical methods.
What are the new substances formed called?
Products
Which part of an atom has no charge?
Neutron
What are the three states of matter?
Solid, Liquid & Gas
How many different elements are in CO₂?
2 — carbon and oxygen
Give one example of a mixture.
salt water, trail mix, air, cereal and milk, etc.
Name one sign that a chemical reaction may have occurred.
Color change, gas formation, temperature change, light, or formation of a new solid (precipitate)
Where are electrons found in an atom?
In the electron cloud/energy levels surrounding the nucleus (outer shells)
What happens to the atoms in a chemical reaction?
The atoms are rearranged to form new substances, but the atoms themselves are not created or destroyed.
What do the small numbers in a chemical formula tell you?
They tell you how many atoms of each element are present.
What is one major difference between a mixture and a compound?
The substances in a mixture are physically combined, while the elements in a compound are chemically joined.
Why can a chemical reaction create a substance with completely different properties from the starting substances?
Because the atoms are rearranged into new combinations, creating new substances with different properties.