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Ch 7 Science Review Notes
Vocabulary
1. element
2. mixture
3. compound
4. chemical formula
5. chemical change
6. periodic table
7. molecule
8. atom
9. density
10. solution
11. matter
12. suspension
13. sublimation
14. solute
15. solvent
Concepts to Know:
16. All matter is made up of atoms. Atoms can join to form molecules. If atoms from
two or more different types of elements join, a compound is formed.
17. A pure element is made up of all of the same kind of atoms.
18. When two or more atoms join, they form a molecule.
19. When two or more different types of elements join, they form a compound.
20. If two items have the same amount of mass, the smallest item would be the
densest because the particles are packed more tightly together.
21. The Periodic Table organizes elements. Each element has a symbol and an atomic
number. The atomic number of an atom is determined by the number of protons in
its nucleus.
22. A compound is formed by a chemical change.
23. When a solute is dissolved by a solvent, a solution is formed.
24. Solutions are made of small molecules that have the same properties throughout
the entire mixture.
25. Heterogeneous mixtures are made of particles large enough to see with the
unaided eye and may have different properties throughout.
26. Both heterogeneous mixtures and solutions are both physical combinations of two
or more substances.
27. The Periodic Table helps us learn about he physical and chemical properties of
the elements. It tells us the name, symbol, and atomic number of each element,
which elements have similar physical and chemical properties, and which
elements can most strongly react chemically with other elements.
28. Elements are substances that cannot be broken down into a simpler form.
29. Molecules are combinations of two or more atoms joined together.
30. Chemical compounds are combinations of tow or more elements that form a
substance with different properties.
31. Oil and vinegar do not dissolve in each other. The liquid that has the lower
density, oil, floats on the liquid that has the greater density, vinegar.
32. C H O is the chemical formula for sugar. The small number to the bottom right of
each element is the subscript. The subscript tells how many atoms of each element
are in the sugar molecule. There are 6 carbon atoms, 12 hydrogen atoms, and 6
oxygen atoms.
33. The three states of matter are solid, liquid, and gas.