New Cards For Test - 2

Front 1

10. Define Atom, Element, Molecule,

Compound, Mixture

Back 1

Atom is the smallest particle of an element

Molecule is created when two or more atoms combine.

Element is a pure substance with the

smallest particle an atom.

Back 2

Compound is a pure substance with the smallest particle a molecule.

Mixture - Two or more elements or compounds mixed together but do not chemically combine.

Front 3

11. Write the chemical formula for a compound formed when 2 atoms of hydrogen combine with 1 atom of oxygen

Front 4

12. How are atoms and molecules related?

Back 4

Molecules are made of two atoms or more

atoms bonded together.

Front 5

13. What is the difference between an element and a compound?

Back 5

The smallest particle in an element is an atom. The smallest particle in a compound is an element.

Front 6

14. What is the difference between a compound and a mixture?

Back 6

Compound - Pure substance where every particle that makes up the substance is the same (chemically combined).

Mixture - Substance with two or more different types of particles (not chemically combined).

Front 7

15. Describe the three combinations that

elements and compounds can combine to form a mixture

Back 7

Mixture of Elements

Mixture of Compounds

Mixture of Elements and Compounds

Front 8

16. How did the model of the atom develop?

Back 8

Over 2,000 years ago, a Greek philosopher described small particles called atoms. Over time, scientists discovered the different parts of the atom - protons, neutrons, electrons and the central nucleus. Today we know that electrons orbit the nucleus but don't know the speed or location. The model is called the Quantum model.

Front 9

17. For the scientists describe their contribution relating to atomic theory.

Back 9

Democritus - Proposed that everything was made of tiny particles called atoms.

Aristotle - matter is made of fire, earth, wind and water.

Dalton - proposed atomic theory. Elements can neither be created nor destroyed, compounds are combinations of various elements.

Back 10

Thompson - discovered the electron.

Rutherford - discovered the nucleus with the gold foil experiment.

Bohr - planetary model of atom. Electrons orbit the nucleus and fixed energy levels

Heisenberg - uncertainty principle. It is impossible to determine both speed and location of electrons as they move around in an atom.