September 13, 2008
Period 1 Biology
Section 6.1 Atoms and Their Interactions
* Atoms are the basic building blocks of all matter.
* Atoms consist of a nucleus containing protons and neutrons. The positively charged nucleus is surrounded by a cloud of rapidly moving, negatively charged electrons.
* Atoms become stable by bonding to other atoms through covalent or ionic bonds.
* Components of mixtures retain their properties—components of solutions do not
Acid: Any substance that forms hydrogen ions (H+) in water and has a pH below7.
Atom: Smallest particle of an element that has the characteristics of that element; basic building block of all matter.
Base: Any substance that forms hydroxide ions (OH-) in water and has a pH above 7.
Compound: Substance composed of atoms of two or more different elements that are chemically combined.
Covalent Bond: Chemical bond formed when two atoms combine by sharing electrons.
Element: Substance that can’t be broken down into simpler chemical substances.
Ion: Atom or group of atoms that gain or lose electrons; has a positive or negative charge.
Ionic Bond: Chemical bond formed by the attractive forced between two ions of opposite charge.
Isotope: Atoms of the same element that have different numbers of neutrons in the nucleus.
Metabolism: All of the chemical reactions that occur within an organism.
Mixture: Combination of substances in which individual components do not combine chemically and retain their own properties.
Molecule: Group of atoms held together by a covalent bonds; has no overall charge.
Nucleus: Positively charged center of an atom composed of neutrons and positively charged protons, and surrounded by a cloud of negatively charged electrons; in eukaryotic cells the central membrane-bound organelle that manages cellular functions and contains DNA.
pH: Measure of how acidic or basic a solution...