BIO104 Chapter 2.1-2.3

Matter

Anything that takes up space and has mass, (solids, liquids, gas) made up of elements

Elements

Substance that cannot be broken down into simpler substances by ordinary chemical means

Essentials

Cells cannot produce them (we get them from food, water, air, outside sources)

Trace Elements

Very small amounts (iron, zinc, iodine)

Atom

Smallest part of an element that displays properties of that element

Atomic Number

Number of protons in the nucleus

Mass Number

Number of protons plus neutrons

Dalton

Measurement

Periodic Table

Used to group elements according to characteristics

Vertical Column of periodic table

Groups

Horizontal Column of periodic table

rows

Isotopes

Atoms of the same element with different number of neutrons

Radioactive isotopes

Emit various types of energy as they decay (UNSTABLE), if it breaks it releases radiation

Uses of radiation

Used for therapy to kill cancer cells and medical imaging

Electrons

Orbit the nucleus

Electron Shells (electron orbitals)

Electron energy, first shell contains 2 electrons, every one after contains 8

Octet Rule

Valance shell is stable with 8 electrons

Valence electrons

Electrons found in valence shell

Inert atoms

Do not react (no space)

Molecules

Form when 2 or more atoms bond together (ex. H2O)

Ions

Charged atoms that form when electrons are transferred from one atom to another (these atoms are gaining or losing electrons)

Ionic Bonding

Type of bond where atoms are losing or gaining electrons (Becoming more positive or more negative)

Electron Transfer

Creates charge imbalance

Charge Imbalance

Creates ionic bonds