Intro to atoms
- 1. Imagine cutting a gold bar in half. Then cut in half again. …and again. …and again. …and again. …and again. Speak up! Could you keep cutting that bar in half forever? Why or why not? How small could you cut up that gold and it still be gold?
- 2. Atoms
- 3. • What is an atom? • An atom is the smallest particle into which an element can be divided and still be the same substance. • Atoms make up elements and elements combine to form compounds.
- 4. • What is an atom? • An atom is made of 3 parts: • Protons (+) • Neutrons (neutral) • Electrons (-) • Protons and neutrons make up the nucleus of the atom • Electrons orbit around the nucleus like planets around the sun
- 5. • Key terms: • Valence electron – electrons farthest from the nucleus (involved in bonding) • Atomic number* = number of protons. *Determines the identity of an element • Mass number = # of protons + # of neutrons • Atomic mass = the average mass of all the known isotopes of an element
- 6. • Even though it is not quite accurate anymore, the Bohr model of the atom is still useful for building a basic understanding of atoms.
- 7. Practice: Draw an atom and label its parts. Your drawing should include: • 3 Protons (+) • 3 Neutrons (neutral) • 3 Electrons (-) • Nucleus Your drawing should fill an entire page!
- 8. Tie your shoes: Divide your page as shown and draw an atom of each of the following elements. Helium atom Beryllium atom Carbon atomBoron atom
- 9. • Cold calls… 1. What are the three subatomic particles in an atom? (Be sure to include their charges!) 2. What 2 subatomic particles are in the nucleus of an atom? 3. Where are electrons found in an atom? 4. What determines the chemical element of an atom? 5. What is a valence electron? 6. What is atomic mass? 7. What is the charge of the nucleus? Why? 8. What is the charge of the atom as a whole? Why?
- 10. Quick Quiz: Draw and label an atom of the element nitrogen.
- 11. Copy and complete the following questions in your composition book. 1. What are the three subatomic particles in an atom? 2. What does the atomic number tell you about an atom? 3. What makes atoms of different elements different? 4. What do atoms of the same element have in common? 5. What 2 things are found in the nucleus of an atom? 6. What is the charge of the nucleus? Why? 7. Where are the electrons? 8. What is the charge of the atom as a whole? Why?