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LN #2 Atoms & their Interactions. Elements. Are pure substances that can’t be broken down into other substances. Elements are made of only one type of atom . All matter can be broken down chemically into about one hundred different elements. Organic Chemistry
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Elements • Are pure substances that can’t be broken down into other substances. • Elements are made of only one type of atom. • All matter can be broken down chemically into about one hundred different elements. • Organic Chemistry • Hydrogen, oxygen, nitrogen and carbon make up more than 96 percent of the mass of a human.
Atomic Structure • Atoms are made up of three particles. • Protons • in the nucleus • positive charge • Neutrons • in the nucleus • no charge • Electrons • in cloud around the nucleus • negative charge • Electron Energy Levels • Level one full with 2 electrons • Level two full with 8 electrons
Compounds • When elements combine!!! • Elements combine so that they can be more stable. • When elements combine a chemical bond is formed between them. • The nucleus determines the chemical identity of the atom. • The electrons are directly involved in forming chemical bonds.
Needs 1 electron to have a full outer energy level. Needs 2 electrons to have a full outer energy level. When electrons are shared all outer energy levels are full. Covalent Bonds • Covalent bonds form when atoms share electrons. • Atoms share electrons because they want their outer energy level to be full. • When the outer energy level is full the atom is more stable.
Needs 7 electrons to have a full outer energy level. Needs 1 electron to have a full outer energy level. Ionic Bonds • An ionic bond is an electrical attraction between two oppositely charged atoms. • Atoms can donate or accept electrons in order to fill its outer energy level. • When electrons are lost or gained the atom becomes an ion and carries an electric charge. • Ionic bonds are weaker than covalent bonds.
H O N C 1 2 3 4 HONC rule Oxygen Hydrogen Needs 1 electron Makes 1 bond Needs 2 electrons Makes 2 bonds Carbon Nitrogen Needs 3 electrons Makes 3 bonds Needs 4 electrons Makes 4 bonds
Acids and Bases are everywhere • Every liquid you see will probably be either an acid or a base. • The only exception is distilled water. • Liquids have ions in them. Ions are what make the liquids acidic or basic. • Ions = atoms with a positive or negative charge resulting from the gain or loss of one or more electrons.
pH scale • The pH scale is used to measure if something is an acid or a base. • The scale goes from 0 to 14. • Acids are found between 0 and 7. • Bases are found between 7 and 14. • Distilled water is in the middle with pH 7.
What does pH stand for? • pH stands for potential hydrogen. • The pH scale measures how many H+ ions there are in a solution. • If there is a lot of H+ ions the pH is low. • If there are a lot of OH- ions, that means the number of H+ ions is very low, so the pH is high
pH and Human Bodies • pH 7.4 is average for human bodies. • Renal and respiratory systems regulate the bodies pH. • Respiratory System • Release carbon dioxide from lungs • Carbon dioxide is a waste product of cells • Cells excrete carbon dioxide into the blood and the blood sends in to the lungs. • Renal System • The kidneys regulate your bodies pH by excreting acids and bases.
Summary • What are atoms? • What are the parts of an atom? • What are the charges on the atom parts? • What are covalent bonds? • What are ionic bonds? • What are acids? • What are bases? • What systems regulate pH?