Chapter 2

Matter Matter is anything that occupies space and has mass. Mass is the quantity of matter an object has.

(contains protons & neutrons) Elements and Atoms Elements are made of a single kind of atom and cannot be broken down by chemical means into simpler substances. Examples: Oxygen, Carbon Atoms are made of protons, neutrons, & electrons Nucleus (contains protons & neutrons) Electrons P N

Parts of an Atom Nucleus: center, contains protons and neutrons Protons: positively charged particles Neutrons: neutral in charge Electrons: negatively charged, located on orbitals outside the nucleus Overall charge of an atom is typically neutral due to (+) inside the nucleus and (–) outside the nucleus.

Electron Orbitals An atoms 1st orbital can hold up to 2 electrons An atoms 2nd through 4th orbital can hold up to 8 electrons. Example: Oxygen 8 (has 8 p,n and e’s) 1st orbital: 2 electrons 8p 8n 2nd orbital: 6 electrons

Compounds Compounds consist of 2 or more elements that are joined by chemical bonds in a fixed proportions. Example: H20 H H O

Bonding Covalent Bonding: when atoms share electrons to bind Example: H20 O H H

Bonding part 2 Ionic Bonding: when atoms bond by transferring electrons for one atom to another. Example: NaCl Sodium gives up its one electron from the outer orbital , now both atoms are stable (their outer shells are full). 11p 11n 17 p 17n

Water & Solutions A solution consists of a solute dissolved in a solvent. Example: plasma (liquid part of blood)

Acids and Bases Acids: 0-7 on a pH scale Taste sour, highly corrosive (stomach acid, hydrochloric acid) Bases (alkaline) 7-17 on a pH scale Taste bitter, slippery feeling to them

pH Scale Acidic Basic 14 7 Neutral Stomach Acid Blood Milk of 7 Stomach Acid Blood Milk of Magnesium Urine Vinegar Water Intestinal Fluid Ammonia

Inert vs. Reactive Inert Atoms: are stable (FULL) on outside orbital, these tend to “look” for other atoms to complete their outer ring Reactive Atoms: are not stable (FULL) on the outside orbital

Synthesis vs. Decomposition Chemical Reactions: process of making or breaking chemical bonds between atoms. Synthesis: A + B  AB Decomposition: AB  A + B

Inorganic Compounds: held together by ionic bonds, no carbon either Water: most important and abundant compound in body. It makes up 60-70% of total body mass. (transports, dissolves, high heat capacity, reduces friction) Salt: creates ions for body Acids/Bases: reactions in body

Organic Compounds: building blocks, contain carbon Carbohydrates: sugars and starches, used as fuel Lipids: fats, phospholipids and steroids Proteins: basic structural material in body Nucleic Acids: DNA, RNA ATP (adenosine triphosphate): energy