Chap 2: The chemistry of life

Mass

anything that has mass occupies a space

atoms

smallest particle of elements

element

• matter made up of only one type of atom

• 92 natural elements

• each symbol has its own element

Molecule

A group of two or more atoms held together by chemical bonds

Ex: H20 and CO2

Compound

• two or more elements combined in fixed ratios

• A compound has characteristics beyond those of its combined elements

Marco elements

• elements needed in large amounts of quantities

• Ex: C,H,N,O,P,S,K

Micro Elements

• elements needed in small amount of quantities

• Also known as trace elements

• Examples: Cu, Co, Zn

Subatomic Particles

Protons- Positively charged (p^t)- located in the nucleus

Neutrons- neutral no charge (o)- located in the nucleus

Electron- neg charge- located in the electron cloud

Isotope

• atoms of the same element with different atomic masses

• Two types

• Radioactive: Where the nucleus decays and leaks particles and energy

• Heavy- Stable nucleus; “heavy” due to differing numbers of neutrons

Electron configuration

• arrangement of electrons outside the nucleus

• electrons are found in: orbitals/shells/energy levels

Chemical bonds

• Forces that join atoms of elements together

• 4 different types- Covalent, Ionic, Hydrogen, van der Waals

Covalent bonds

• forms when atoms of elements share electrons

• Forms of liquids and gas at room temp

• strong

Two different types

Non-polar- when atoms of elements equally share electrons resulting in a molecule that is neutral or has no charge

Polar Covalent Bonds- forms when atoms of elements unequally share electrons

• Result: compound has “charge” (t/e) charged

• Properties: Polar/ Charged (hydrophilic)

Ionic Bonds

form when atoms of elements clonate/ share electrons, forming charged atoms- ions

Ions-

• cation: Positively charged

• Anion: negatively charged

Hydrogen Bonds

• Forces that form from the attraction of a (H^t) hydrogen atom and (-) atom of another element

Van der waals forces

weak, temporary attractions between molecules that arise from random shifts in electron distribution