1. 2.1 Atoms, Ions, and Molecules Updates: 32.1 unit guide questions due Monday Homework: –reading unit 2: 2.1, 2.4 –Case study due Tuesday! Unit 2 quizzes resume tomorrow: 32.1, 2.1 Unit 1 test MC retakes must be completed by Wed PM

2. 2.1 Atoms, Ions, and Molecules Collins Writing: Capture Ideas Study the short answer question provided. Brainstorm – get some ideas on paper related to the content from last week. Strive for 2 lines per prompt Questions and/or guesses are permitted

3. 2.1 Atoms, Ions, and Molecules Updates: Unit 2 quizzes continue tomorrow: 32.1, 2.1 Case study due Homework: –reading unit 2: 2.1, 2.4 Unit 1 test MC retakes must be completed by Wed PM

4. 2.1 Atoms, Ions, and Molecules LEQ: What are organisms and nutrients made of? Activator: –Describe the three key ingredients of life. –What do you think are the implications about what we know of life on Earth? Key terms: atom, element,

5. 2.1 Atoms, Ions, and Molecules Quiz: 1.The basic unit of matter is called a(n): a.Atom b.Cell c.Element d.Electron 2.Carbon, hydrogen, and oxygen are all examples of: a.Cells b.Subatomic particles c.Elements d.molecules

6. 2.1 Atoms, Ions, and Molecules Matter (in life) was made in “star nurseries” The most widely accepted hypothesis of Earth’s origins is the nebula hypothesis.

7. 2.1 Atoms, Ions, and Molecules The Elements: Forged in Stars How does a star get its energy to glow? What elements make up young stars? What could you infer about the age of a star if you were to find evidence of iron being present?

8. 2.1 Atoms, Ions, and Molecules Updates: Unit 2 quizzes continue tomorrow: 32.1, 2.1 Case study due Homework: –reading unit 2: 2.1, 2.4 Unit 1 test MC retakes must be completed by Wed PM

9. 2.1 Atoms, Ions, and Molecules Quiz: 3. The basic unit of matter is called a(n): a.Atom b.Cell c.Element d.Electron 4. Carbon, hydrogen, and oxygen are all examples of: a.Cells b.Subatomic particles c.Elements d.molecules

10. 2.1 Atoms, Ions, and Molecules LEQ: What are organisms and nutrients made of? Activator: –Describe the three key ingredients of life. –What do you think are the implications about what we know of life on Earth? Key terms: atom, element, isotope

11. 2.1 Atoms, Ions, and Molecules Several dozen elements are essential for life on Earth: Atoms are the basic units of matter –They exist in varieties called elements Essential elements include: –Carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur –CHNOPS H O Hydrogen atom (H) Oxygen atom (O)

12. 2.1 Atoms, Ions, and Molecules Oxygen atom (O) Nucleus: 8 protons (+) 8 neutrons outermost energy level: 6 electrons (-) inner energy level: 2 electrons (-) Protons determine the element (type of atom) –(+) charge Electrons participate in bonding –(-) charge Neutrons make some elements radioactive isotopes

13. 2.1 Atoms, Ions, and Molecules Oxygen atom (O) Nucleus: 8 protons (+) 8 neutrons outermost energy level: 6 electrons (-) inner energy level: 2 electrons (-)

14. 2.1 Atoms, Ions, and Molecules

15. Valence Electrons The electrons in the outer most electron shell are called valence electrons The shell containing electrons that is furthest from the nucleus is called the valence shell The number of electron shells with electrons is the same as (=) the period number Atoms will try to gain or lose electrons to have a full valence shell

16. 2.1 Atoms, Ions, and Molecules Valence Electrons Each electron shell can hold a certain number of electrons Electron shells are filled from the inside out Noble Gases have full outer electron shells All other elements have partially filled outer electron shells Electron Shell Number of Electrons 12 28 38 418 5 632 7

17. 2.1 Atoms, Ions, and Molecules Bohr Diagrams Find out which period (row) your element is in. Elements in the 1 st period have one energy level. Elements in the 2 nd period have two energy levels, and so on.

18. 2.1 Atoms, Ions, and Molecules Bohr Diagrams C C 1)Draw a nucleus with the element symbol inside. 2)Carbon is in the 2 nd period, so it has two energy levels, or shells. 3)Draw the shells around the nucleus.

19. 2.1 Atoms, Ions, and Molecules Bohr Diagrams 1)Add the electrons. 2)Carbon has 6 electrons. 3)The first shell can only hold 2 electrons. C C

20. 2.1 Atoms, Ions, and Molecules Bohr Diagrams 1)Since you have 2 electrons already drawn, you need to add 4 more. 2)These go in the 2 nd shell. 3)Add one at a time - starting on the right side and going counter clock-wise. C C

21. 2.1 Atoms, Ions, and Molecules Bohr Diagrams 1)Check your work. 2)You should have 6 total electrons for Carbon. 3)Only two electrons can fit in the 1 st shell. 4)The 2 nd shell can hold up to 8 electrons. C C

22. 2.1 Atoms, Ions, and Molecules Heavy isotopes of atoms are used by scientists

23. 2.1 Atoms, Ions, and Molecules Discussion: Radioactive Decay of Carbon-14 What is the most common form of carbon? How is carbon-14 different? What does it mean to say that an isotope is unstable?