Atom's Nucleus Most of an atom’s mass is contained in the nucleus. Proton – a subatomic particle with a positive charge Neutron – a subatomic particle with no charge (electrically neutral) It would take 3 million carbon atoms to stretch across the period at the end of a sentence in your text book!!!!!!
A subatomic particle with a negative charge. Electron’s have very little mass. They move around the nucleus at a high rate of speed, but are held close by its attraction to protons in the nucleus.
Isotopes Alternate forms of an atom They have the same number of protons but differ in the number of neutrons. Atomic Mass = Protons + Neutrons
Radioactive Isotope An isotope in which the nucleus decays giving off radiation in the form of matter and energy. Uses: “Biological Spies” – injected into cells and then as the isotope decays instruments detect the radiation and follow the cells.
Atomic Number The number of protons found in a particular atom. All atoms of the same element have the same number of protons.
The # of protons determine the elements properties. An atom is said to be electrically neutral if left alone. The # of protons = The # of electrons ……………… .however, the # of electrons doesn’t remain constant!
The structure of an atom will determine the chemical properties of a particular substance.
Electrons and Reactivity An electron’s reactivity is dependent upon the atom’s electrons in the highest energy level. Atoms that naturally have full energy levels have the tendency to NOT REACT!!!
Oxygen O 65% <ul><li>Forms Water </li></ul><ul><li>Needed for Respiration </li></ul><ul><li>Released After Photosynthesis </li></ul>
Carbon C 18.5% Organic matter makes up all living things Carbon is found in all organic matter
9.5% Hydrogen helps to form water Hydrogen is found in all organic matter
Nitrogen N 3.2% Found in proteins Found in DNA Important in plant growth
These are the elements that make up less then .01% of your body. They are however critical to the health of your body. A healthy diet is critical to maintain proper trace elements levels. Trace Elements
Compound – 2 or more different elements that are chemically combined Compounds occur when one element interacts with another element.
What holds together elements in compounds? <ul><li>Electrons are G, T, S ! </li></ul><ul><li>They are given , taken , or shared by the elements in a compound. </li></ul><ul><li>They are also the part of the atom that takes part in chemical reactions </li></ul>Chemical Bonds
Ionic Bonds Ionic bonds are bonds that occur when an atom transfers electrons to another atom.
Ionic Compounds ***Compounds formed by the attraction of ions*** Ex . NaCl Na + + Cl - A bond forms when Na loses an e - and Cl gains an e -
Ions Atoms are usually neutral. (# of protons = # of electrons) Ions - electrically charged atoms Positive Ion = an atom that loses an electron Negative Ion = an atoms that gains an electron
Ionic Compounds are important to the human body . <ul><li>Na + and K + and Cl - help to move nerve impulses. </li></ul><ul><li>Ca + helps muscles to contract. </li></ul>
Covalent Bonds Covalent bonds occur when two atoms share electrons to form a bond.
Molecular Compounds Molecular compounds are compounds made of molecules. Molecule = a group of atoms held together by energy via covalent bonds
Chemical Formula Tells you the # what kinds of atoms are in each molecule. CaCl 2 KCl PbCl 2 CH 4 H 2 O 2 NaCl
Molecule vs. Compound vs. A molecule is a compound if it has more then one type of atom. Oxygen gas (O 2 ) is a molecule but not a compound. Water (H 2 O) is a molecule and can be a compound.
Chemical Reaction During a chemical reaction, bonds are breaking and atoms are rearranging to form new bonds. Molecules become rearranged into different molecules. A chemical reaction can release or absorb energy.
Example of a Chemical Reaction: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Sun’s Energy Elements properties change after a chemical reaction!
Life's Dependency on Water All living things depend on water. Our bodies consist of 60-70% water!
Unique Properties of Water One water molecule = 2 H atoms and 1 O atoms Because of the 8 protons that exist in oxygen versus the 1 proton that exists in hydrogen, oxygen pulls the electrons toward it much more strongly when the bonds in the molecule form!!
A molecule in which opposite ends have opposite electric charges.
Hydrogen Bonds The attraction of the hydrogen atoms of one molecule and the negative atom of another water molecule. There is no transfer of electrons, so the bond isn’t as strong as an ionic bond.
The attraction that occurs between unlike molecules.
The tendency of molecules of the same kind to stick to one another.
Help to transport water from roots to the leaves of trees. Ex. Cohesion – the surface tension on water allows insects to “skate” across water.
Because of the hydrogen bonding, water has the ability to resist temperature change.
The total amount of energy associated with the random movement of atoms and molecules in a sample of matter.
The measure of average energy of random motion of particles in a substance.
Importance of Temperature Moderation Water takes longer to heat because of the energy it takes to break those hydrogen bonds. Ex. Oceans moderate surrounding lands.
Long lasting hydrogen bonds in the ice spread out the water molecules making it less dense then the liquid form.
The bottoms of lakes and ponds freeze last. This keeps the nutrient rich muds open and the ice on top insulated the water below.
Solution – a uniform mixture of 2 or more substance Solute – the substance that is dissolved Solvent – the substance that does the dissolving and is present in a great amount Aqueous Solution – a solution in which water is the solvent
In aqueous solutions, a small amount of the H 2 O molecules break apart and H + and OH - ions are formed. In order for the life processes in living systems to work properly the number of OH - and H + ions must balance one another out.
An acid is a compound that donates additional H + ions in solution.
A compound that removes H+ ions from an aqueous solution. Ex. Ammonia
Substances that cause solutions to resist changes in pH. . Ex. Blood’s pH = 7.4. If something acidic is introduced into the bloodstream, a buffer will be present to take up the extra H + ions
ENERGY Anything that brings about change. Energy can hold matter together or break it apart Cooking – breaks the bonds of food
Matter and Energy Matter Energy Examples: Atoms Living Things Rocks Soil Air Examples: Sunlight Electricity Heat Chemical energy
Calcium Found in Bones and Teeth Helps to Control Stomach Acid Ca 1.5%
Sulfur S 0.3% Found in proteins such as hair, skin, and muscles
Sodium Sodium 0.2% Sodium is needed for nerve impulses
Chlorine Chlorine Needed for passing nerve impulses 0.2%
0.1% Important in photosynthesis and is found in chlorophyll.
99% of all living matter consists of the following elements: C H O N P S
Examples of Compounds H 2 O = ___ H atoms and ___ O atom CO 2 = ___ C atom and ___ O atoms O 2 = ___ atoms C 6 H 12 O 6 = ___ C atoms, ___ H atoms and ___ O atoms
Mixtures Mixture – a combination of substances in which individual substances retain their properties Ex. Salt and sugar, oxygen and carbon dioxide
Solution – two or more substances evenly mixed, one substance is dissolved in another What Is A Solution?
Suspension – a liquid or gas has another substance evenly spread in it What Is A Suspension? Ex. Blood and plasma, oil and water
Organic Compounds They ALWAYS contain C and H and are associated with LIVING things or ONCE living things The 4 class of organic compounds include the following: Fat and Lipids Carbohydrates Nucleic Acids Proteins
Carbohydrates Subunit: C, H, and O Uses/Roles: sugars, starches and cellulose. They supply energy for the cells processes, from plant structure (cell wall), and are used for short-term energy storage
Lipids Subunit: C, O, H, and P Uses/Roles: Fats, oil, waxes, and cholesterol. Contain large amounts of long term storable energy
Proteins Subunit: C, O, H, N, and S Uses/Roles: Muscles, skin, hair, and enzymes. They regulate cell processes, help to jump start cell activities. Help to build cell structure.
Nucleic Acids Subunit: C, O, H, N and P Uses/Roles: Found in DNA and RNA. Carry hereditary information and is used to make proteins
Inorganic Compounds “ Not of Life” The most important Inorganic compound to life is --- ???
WATER <ul><li>Water is vital to all life. </li></ul><ul><li>50 - 60% of human body mass is due to water. </li></ul><ul><li>We can live weeks without food, but only days without water. </li></ul><ul><li>Water is a good insulator and it helps to maintain cell temperature. </li></ul><ul><li>The fact that ice floats helps to save many water organisms during cold winters. </li></ul>
Additional Inorganic Compounds Calcium Phosphate - adds strength to bones Hydrochloric Acid - breaks down food in the stomach Sodium Bicarbonate - helps digestion to occur Salts - send messages along nerve cells