Chemistry Review. Please seek out help if you have not learned these concepts before!

Transcription

1 Chemistry Review This slide show is chemistry review! We are not covering this section in class. Therefore IF YOU NEED HELP with this material, go and see your teacher ASAP! The information that we do in class will build upon this. If you do not understand the concepts in this document, you will have a hard time understanding what we do in class. Please seek out help if you have not learned these concepts before!

2 CHEMISTRY The study of matter. (Anything that has mass and takes up space)

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4 Why chemistry in biology class? When we spent all that time studying diffusion, solutes, semipermeable membranes and water, we were really looking at the way that matter behaves and how the cell is affected by that matter (chemicals). When we studied the organelles, they are all composed of chemicals, work with chemicals, produce chemicals. Soon you ll see that chemistry (bio-chem) is really studying how life uses chemicals to live..but before we can talk about what the cells do with the chemicals, you need to understand a bit more about chemistry! But, before we move on, if you aren t convinced that you are a series of chemicals and their actions:

5 What you need to know: Basic components of an atom. (With charges) How electrons fill orbits. (Valence) Basics about periodic table, how to determine; # of neutrons, electrons, protons and mass When atoms will react

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7 Elements A substance that contains all the same type of atom. Fundamental forms of matter 92 occur naturally on Earth

8 Most Common Elements in Living Organisms (the ones you need to Oxygen Hydrogen Carbon Nitrogen Phosphorus know)

9 What Are Atoms? Smallest particles that retain properties of an element Atoms can t be broken apart by normal means Made up of subatomic particles: Protons (+) Found in the nucleus/add to mass Neutrons (no charge) Found inside the nucleus/add to mass Electrons (-) Located outside the nucleus

10 Atomic Number Number of protons and electrons (in neutral atom) All atoms of an element have the same atomic number Atomic number of hydrogen Atomic number of carbon

11 Mass Number Number of protons + Number of neutrons Mass number (rounded) atomic number = neutrons

12 Chemical Equations In a chemical equation the big number in front is how many of that molecule is in the equation. The smaller number after is how many atoms of that element are in each molecule. CO 2 = 1 carbon atom and 2 oxygen atoms bonded together 6CO 2 = Six molecules of CO 2 how much of the substance is needed to react.

13 Counting Atoms! CH4 Carbon= Hydrogen= COH4(CH2)4 Carbon= Oxygen= Hydrogen= Multiply all the atoms in the parenthesis with the co-efficient and then add like atoms together! C2(COH)5CH3 Carbon= Oxygen= Hydrogen=

14 Counting Atoms! CH4 Carbon=1 Hydrogen= 4 COH4(CH2)4 Carbon=5 Oxygen=1 Hydrogen= 12 Multiply all the atoms in the parenthesis with the co-efficient and then add like atoms together! C2(COH)5CH3 Carbon= 8 Oxygen= 5 Hydrogen= 8

15 What Determines If Atoms Will Interact? The number and arrangement of their electrons

16 Electrons Carry a negative charge Repel one another (like magnets) Are attracted to protons in the nucleus(- to +) Move in orbitals = volumes of space that surround the nucleus

17 Electron Orbitals Orbitals, based on their size can hold different amounts of electrons. Atoms differ in the number of occupied orbitals Orbitals closest to nucleus are smaller in size and have lower energy and are filled first Filling pattern is 2, 8, 8 (beyond that you will not be responsible for in this course)

18 Shell Model SODIUM CHLORINE 11p+, 11e - 17p+, 17e - First shell 2 electrons Second shell holds up to 8 electrons CARBON OXYGEN 6p+, 6e - 8p+, 8e - HYDROGEN HELIUM 1p+, 1e - 2p+, 2e -

19 The electrons in the outer most shell is called the valence electrons. These are the electrons that determine how the atom will bond to others. The A number at the top of each column on the periodic table lets you know how many valence electrons the elements in that group have.

20 Electron Vacancies 8 valence electrons is ideal for an atom. Once there are 8 electrons the atom is happy and stable. Unfilled valence shells make atoms likely to react Hydrogen, carbon, oxygen, and nitrogen all have vacancies in their outer shells This means these atoms like to bond with other atoms to fill their shells. (Orbitals)

21 Filled Valence = Happy atom Electrons will move, or be shared between atoms to try and fill the outer shell. If the outer shell is already full (noble gas) it is very unlikely to react. If there is only 1 space to fill or only 1 in the valence level they are volatile. Determine what charge the atom would have with a full valence shell.

22 Remember, come to an extra help session or use Aca-prep ASAP if you are struggling with the basics of chemistry!!!