Chapter Two: Chemistry
An atom is the smallest complete unit of an element and is made up by the subatomic particles known as protons, neutrons, and electrons. Their charges are as follows
-Neurons = neutrally charged
-Protons = +
-Elections = -
*typically atoms are neutrally charged b/c the # of protons and electrons are equal, causing them to balance out*
Atomic Structure
-nucleus is in the center and consists of protons and neutrons
-nucleus is orbited by rings of electrons
Molecule - Particle composed of two or more joined atoms
Ex) water molecule is H2O, two hydrogen atoms joined with an oxygen atom makes a water molecule
Molecular formulas tell what atoms are there and how many there are.
Ex) H20 is the molecular formula for water, which consists of 2 hydrogen atoms and 1 oxygen atom.
Atomic Number

The number of protons present in the atom
 If you’re looking at the set-up, it’s the number in the top left corner of the element info boxes in the Periodic Table
Bonding (2 types)
Ionic Bonding- when atoms with opposite charges are attracted to one and other, no sharing of electrons is involved, instead electrons are given up
Covalent Bonding- electrons are shared-in pairs- and shared in motion

Electrons are bonded in different ways and orbit the nucleus of an atom.

Valence electrons are the electrons on the outer shell/shelf, orbiting the nucleus, they are the atoms “bargaining chips”

Isotopes- an atom that has the same number of protons as other atoms of an element , but a different number of neurons
Ex) Carbon 12, carbon 14, all carbon, but different types b/c each one differs in the number of neurons present
Ions- an electrically charged atom or molecule.
-they are formed when an atom gains or loses an electron
Ex) I lost an electron….Are you sure?....I’m positive!!!!!!!!!!!!!!!!!!!!!!!!! (: pH Scale:
Strong Acid Neutral Strong Base

---l-------------------------------------------------l---------------------------------------------l-----

1 7 12
*the body wants to keep things at a neutral pH of 7 to maintain homeostasis *
Acid vs. Base:
Acid- o Feels life water o pH less than 7 o sour o releases H+
Base- o slippery o pH more than 7 o bitter o contains OH-

Organic Compounds (must contain both Carbon & Hydrogen) Include:
-carbohydrates
– provide energy and structural materials for cells, contain C, H, and are broken up into the categories of monosaccharide, disaccharide, and polysaccharide. An example of a carb is a starch.
-lipids – store energy, insulate, provide shock absorption, compose cell membranes, help with stability, and compose some hormones. 3 types (triglyceride, phospholipid, and steroid) and an example of a lipid is cholesterol.
-proteins
– composes enzymes, structural material, energy source, compose antibodies, act as receptor cells. A type is a polypeptide chain made up of many different combos of amino acids.
-nucleic acids – building blocks are known as nucleotides (each nucleotide contains a sugar, phosphate, and base) They are key components in DNA and protein synthesis

Amino acids are the building blocks of proteins, there are 20 different types and they are held together by very weak H-bonds
 Monosaccharide’s
are simple sugars such as glucose
 Monomer is molecule that can be bonded to other identical molecules to form a polymer.
Starches/Simple Sugars:
-they break down quickly b/c they have shorter chains, while complex carbs take longer to break down b/c they have longer chains
Ex) candy before a big game vs. a Pasta Party before a big game