Chapter 2 Flashcards
Element
Any Substance that cannot be broken down to other substances
Compound
a substance containing two or more elements
Essential Elements
20-50% of the elements that an organism needs to live a healthy life and reproduce C, O, H, N 96%
Trace Elements
Are required in all organisms but only in small quantities
Atom
Smallest unit of meter that contains properties of an element
Atomic Nucleus
Center of atom houses protons and neutrons has a positive charge
Atomic Number
Written as a subscript, Tells the number of protons and electrons
Mass number
above the atomic number shows the number of protons ans neutrons
Isotopes
Some atoms that have more or less neutrons than other atoms of the same element
Radioactive isotope
nucleus decays spontaneously- may become another element
Energy
capacity to cause change
Potential Energy
energy that matter possesses because of its location or structure
Electron Shells
Different energy level that an electron may be on, energy is lost by coming closer to nucleus, energy is gained by moving away
Covalent Bonds
Sharing of a pair of valence electrons, and are the strongest
Molecule
Two or more elements held together by covalent bonds
