Biology Flashcards
(Unit 2)
Atom
Building block of matter
Nucleus
Center of an Atom
Protons
(+) Positive Charge
Nuetrons
(=) Nuetral
Electrons
(-) Negative
What is an Element?
pure substance, cannot be broken down
Isotopes
Atoms of same element w/ different # of neutrons. C-14
What is Carbon Dating?
Measure of radioactive (unstable) C-14 levels relative to C-12. Half Life =5730 years
Compounds
pure substance, can be broken down (chemically), two or more combined elements.
Covalent Bond
electrons that are shared between
atoms.
Result of Covalent Bonds?
Compound/Molecule is formed
Ionic Bond
The attraction between oppositely charged atoms
Ion
An atom if it gains or loses an electron.
van der Waals Forces
attractive forces between the positive and negative regions on molecules
Chemical Reactions
Rearrangement of
molecular or ionic structure.
Reactants
Starting substances
Products
Substances formed by a reaction