What’s Important About the Nutrition Label?

1. What’s Important About the Nutrition Label? • What does the label tell you? • Why is this important?

2. Unit 3:The Chemistry of Life • Unit Objective: • To identify the carbon-based organic molecules of life and understand the roles they play in life processes. • Lesson Objective: • To know how an atom is constructed and how each element’s properties determines how the formation of compounds (bonding) takes place. Only copy down underlined material. Everything else is there for support.

3. First Question… • Why do we study CHEMISTRY in BIOLOGY class… • https://youtu.be/fgQLyqWaCbA • So. Why do we?...

4. What Are Organisms Made Of? • Every organism is different depending upon it’s role or needs but there are basic elements that are universal to life on Earth.

5. The Basic Compounds of Life. • Regardless of the amount, most organisms use elements to form these Macromolecules of Life. • Fats • Proteins • Sugars • Nucleic Acids. • These are the fundamental molecules of life that you will be required to know. • These carbon-based molecules are known as Organic Compounds. • Another molecule you will learn about in this mini-unit is water.

6. Essential Questions Objectives • How does hydrogen, carbon, and oxygen combine to form molecules that participate in living systems? • What do these molecules do to support life? • To review/identify what makes up matter. • To know the elements that form most organic molecules. • To review/understand why atoms form bonds. • To understand how and why these bonds are essential for life by forming the carbon-based organic molecules of life. • This information will help you soon be able to explain how these molecules participate in important processes in living things.

7. 1st Step • Get into groups. • Use your resources to fill in the blanks and answer the questions. • Tomorrow we’ll discuss and get any questions answered.

8. Vocabulary • Atoms • Element • Valence electrons • Compound • Molecule • Ion

9. Before You Learn About the Organic Macromolecules… • You must understand that all bigger molecules are built of smaller pieces. • Everything of atoms… • Sometimes arranged into basic molecules. • These smaller pieces are called… • These will sometimes be called… (a.k.a.) • What is a subunit? • Something that is combined with other subunits to build something bigger. SUBUNITS BUILDING BLOCKS or MONOMERS

10. Atoms • All matter is made of very small particles called atoms. • An atomis the smallest unit of matter that cannot be broken down by chemical means. • Every living and nonliving thing is made of matter. • Matter is anything that has mass and takes up space.

11. Atoms • The atom is composed of three main types of smaller “subatomic” particles. • Protons: positively charged particles. • Neutrons: particles with no charge. • Electrons: negatively charged particles.

12. Atoms • The particles are in two specific areas: • The nucleus. • The electron cloud. • Protons and neutrons are in the nucleus. • Electrons are in various energy levels contained in the electron cloud around the nucleus.

13. B What are the parts of an atom? C A D

14. How Is an Atom Built? • Find carbon on the periodic table. • This is the information for the element CARBON • Notice its row and column. • Every box represents a different element. • An element is any quantity of a substance that is 100% the same type of atom. • Being the same type means they have the same # of protons. • Ex: Diamonds are always the element carbon, regardless of the size, because every atom has 6 protons.

15. CHNOPS: What are the Most Abundant Elements in Biology? • The six highlighted below are the most abundant elements in the bodies of most biological organisms. • Take out the periodic tables & Mark these in your Periodic Table.

16. Reading the Periodic Table • Atomic Number • Symbol • Name • Atomic Mass

17. Atomic Numbers, Mass, Electrons… • The boxes give a lot of information. • How do you know how many protons, electrons, and neutrons an element has? • It’s all based upon the atomic number found in the periodic table. • Atomic # = # protons • # electrons = # protons • # neutrons = atomic mass - # protons.

18. What Happens When an Atom Gains or loses an Electron is Ionic. • Usually, atoms by themselves if stable will have equal numbers of protons & electrons. • If this is the case the charges cancel and they are neutral. • If an atom gains or loses electrons they become ions. • Ions are atoms that have a charge because the proton-electron numbers don’t match. • Ions are formed by electrons ‘jumping’ from one atom to another.

19. + - Na Cl Formation of Ions: Count the p+ & e- before & after the exchange… Anion: A negatively charged ion. Cation: A positively charged ion.

20. Special Circumstance: Isotopes Elements • Recall, elements are all the same type of atom because every atom has the same number of protons. • For example, every atom for any amount of the element carbon has six protons. • There are several types of carbon though. • Atoms of an element can have different numbers of neutrons. • Isotopes are atoms of elements that have a different number of neutrons. • Isotopes create challenges and benefits because bonds form differently and are usually radioactive to a degree.

21. Isotopes • Because Isotope atoms have the same number of protons, and also electrons, isotopes have the same chemical properties. • However, isotopes are unstable and release radiation as they decay (shed the extra neutrons) • Some radiation is worse than others.

22. The Numbers Really Matter • The numbers represent an atom’s proton, neutron, and electron number when it is un-bounded and electrically neutral. • Atoms are rarely like this, stable, in nature. • Mainly because the electrons are always flying around. electron

23. The Energy Levels • Atoms are usually represented as a nucleus surrounded by rings. • The rings are energy levels. • The rings exist because e- can’t occupy random or the same space at the same time. • There are rules to how the e- are distributed. • The row (going from top to bottom) tells you how many rings the atom has. • Hydrogen is in the 1st row = one ring • Nitrogen is in the 2nd row = two rings • Shown to the right. • How many rings does iodine have? • These are the atom’s energy levels.

24. Reading the Periodic Table • The Column tells you how many electrons in the outer shell (valence electrons). • The Row tells you how many rings (Energy levels)

25. The Outer Ring… The Valence Shell • Remember, electrons are orbiting the nucleus in the region called the electron cloud... In different energy levels (orbitals). • The outer ring, called the valence shell,is the important one. • This shows you the valence shell electrons. • In the valence shell bonding happens.

26. The Outer Ring • The outer most edges of this cloud is called the valence shell. • There is a strict rule for how many electrons are in this valence shell. • For most groups of atoms, you can determine the # of valence shell electrons from the column it’s in. • The column determines the valence shell electrons. • Group 1A (hydrogen, etc.) has one valence electron. • Group 2A (beryllium, etc.) has two. • This rule only applies to A groups though. • How many valence electrons does phosphorus have? • A: 5

27. Concept Check • On your handouts (back side of the periodic table), complete the blank atom for the element carbon. • Draw the: • Correct # of electrons • Correct # of electron in the valence shell • Correct # of protons • Correct # of neutrons • Put them in the correct places.

29. Representing the Atom • Lots of Atom Models • Which one’s right? • Depends on the application

30. How do you show bonds?… Lewis Dot Structures are best Shows only symbol & the valence e- that participate in bonding.

31. Bohr’s V. Rutherford’s - - - - - - + + + + + + - - - + + + + + + - - - - - - - Same Orbit Different Orbits

32. + + + + + + Where electrons actually are…Schrödinger • Q: Can you identify where the electron is? • A: No! because the electrons never stop moving!

33. Representing the Atom • Bohr’s Diagram • Shows the nucleus, all energy levels, and electron distribution. • Lewis Structure • Shows the atomic symbol & valence e-. • Shows the nucleus (with p+ & n0) plus all inner energy levels (& electrons) represented by the atomic symbol. • Usually the easiest one to use.

34. Practice. Create the Bohr & Lewis Structure for… • Oxygen • Sodium • Chlorine • Uranium

35. CW/HW Answers

36. CW/HW Answers Sorry, bad example

37. Chemical Bonds • Electrons in the valence shell are called valence electrons. • The number 8 is special. • This determines what atoms will bond with what. • Write this just above IX. Chemical Bonds • *OCTET RULE* (Generally speaking) Atoms tend to combine with each other such that eight electrons will be in the valence shell. • The reason is stability! • Regardless of the reason, when atoms are held together a force called a chemical bond holds them. • There are three types of bonds that you need to know. • Ionic bonds • Covalent bonds • Hydrogen bonds.

38. Types • There are three types of bonds that you need to know. • Ionic bonds = When atoms SWAP electrons creating ions that attract. • Covalent bonds = When atoms SHARE electrons to create molecules. • Hydrogen bonds = When polar molecules interact with one another. • There is an order of strength… • Covalent > Ionic > Hydrogen. (covalent is the strongest)

39. Valence electrons: Do the Bonding

40. Special Circumstance: Noble Gasses • Some atoms won’t bond with other elements because they already have 8 valence electrons. • These are called Nobel Gasses. • These are group 8A (all the way on the right).

41. Chemical Bonds • Every other element will bond with other elements to get to 8 valence electrons. • Chemical bonds form between groups of atoms because atoms become stablewhen they have eight electrons in the valence shell. • When atoms of different elements combine, a compound forms. • A compoundis a substance made of the bonded atoms of two or more elements.

42. Common Compounds • Ammonia (NH3) • Water (H2O) • Methane (CH4) • Glucose (C6H12O6) • Salt (NaCl)

43. Ionic Compounds Ionic Bonding • Atoms can sometimes achieve a stable valence level by losing or gaining electrons. • When this happens, the charge of the atom changes slightly and an ion is formed. • [An ion is an atom or group of atoms that has an electric charge because it has gained or lost electrons.] • Opposite charges attract. • The attractive force between oppositely charged ions is an ionic bond.

44. How Do You Know How Many Electrons Get Exchanged? • It is all based upon the number of valence electrons for the element in its basic form. • The metals on the left usually give electrons because they are closer to 8 if they lose a few. • The non-metals on the right usually gain electrons because they will achieve 8 if they gain just a few.

45. Find These Elements on you Periodic Table Gains e- Carbon Gainsor Loses e- Loses e- How close are these elements to achieving 8 in their valence shell? Is it faster to gain a few or lose a few? The numbers of e- gained/lost are variable & correspond to how many they need. What about carbon?

46. + - Na Cl Complete B1 from handout. Formation of Ions: Count the p+ & e- before & after the exchange…

47. How Do You Show the Bonds? • Ionic Bohr Model Or… Lewis Structure We use Lewis Structures which only show the valence electrons.

48. Show the bonding of Na with Chlorine • Figure out how many electrons sodium loses. • How many does chlorine need? • Find these and fill these out on your sheet. • -1 for sodiums • +1 for chlorine • Draw the arrow showing the electron moving. Lewis Structure

49. I I Example: MgI2 • WHY? +2 -1 -1

50. Since each chlorine received one electron what should each charge be? Cl Cl Magnesium chloride. (Just like B2): Since Magnesium donated 2 electrons what should its charge be? +2 -1 -1 When Magnesium loses its outer electrons it exposes its next lower energy level, which happens to have 8 electrons.