Atomic Mass atomic mass is not a whole number because it represents the average element the mass of an electron is so small it is not significant and not represented in atomic mass The average mass of protons and neutrons in an element
Atomic Number The number of protons in the nucleus of one atom of an element 2012 Rice University All Rights Reserved
Property The physical and chemical characteristics of a substance or element 2012 Rice University All Rights Reserved
Periodic Table of Elements A table showing the chemical elements arranged according to their atomic numbers 2012 Rice University All Rights Reserved
Group 1 Groups The columns on a Periodic Table that arrange the elements by the number of electrons that are in the outermost shell 2012 Rice University All Rights Reserved
Periods Period 1 Period 5 The rows in a Periodic Table that classify the elements by the number of electron shells 2012 Rice University All Rights Reserved
Metals Most elements are metals; they are typically solid, shiny, malleable, and good conductors of heat and electricity (shaded in grey above)
Non- metals Elements typically not shiny, usually a gas or brittle solid, not malleable, and poor conductors of heat and electricity (shown in white above)
Metalloids 2012 Elements that have properties of both metals and nonmetals; sometimes referred to as semiconductors Rice University All Rights Reserved
Noble Gases Unreactive nonmetals in Group 18 of the Period Table 2012 Rice University All Rights Reserved
Element A pure substance that cannot be separated into simpler substances by physical or chemical means
Electron Shell A specific area where electrons of the same energy level are found
Atomic Symbol The atomic symbol for Helium A one- or two-letter notation used to represent an atom of a particular element
AMU Stands for Atomic Mass Unit; is used to indicate mass on an atomic or molecular scale
Reac3vity The rate at which a chemical substance tends to undergo a chemical reaction
Lanthanide Series A series of metallic elements, included in the rareearth metals listed in Group 3 of the Periodic Table
Ac3nide Series The series includes the 15 metallic elements in Group 3 with atomic numbers 89-103. They are all radioactive and release energy when they decay. Some are synthetic, only formed in science laboratories.
Group A: Main Group Elements Elements in Periodic Table groups 1A (except hydrogen), 2A and groups 3A to 8A
Group B: Transi3on Elements The 38 elements in groups 3B, 4B, 5B, 6B, 7B, 8B, 1B, and 2B; the transition elements are both ductile and malleable and conduct electricity and heat
Alkaline Earth Metals Metals found in Group 2A of the Periodic Table; all alkaline earth elements have an oxidation number of +2, making them very reactive. Because of their reactivity, the alkaline earth metals are not found free in nature.
Alkali Metals Metals found in Group 1 of the Periodic Table (except hydrogen); compared to other metals, they are soft and have low melting points and densities
Subatomic Particles Hydrogen atom = 1 proton and 1 electron Pure corn syrup; 100% glucose Carbon atom = 6 protons, 6 neutrons, and 6 electrons Oxygen atom = 8 protons, 8 neutrons, and 8 electrons A model of a single glucose molecule Particles that are smaller than the atom 2012 Rice University All Rights Reserved
Matter Anything that has volume and mass 2012 Rice University All Rights Reserved
Atom - - + + + + - - The smallest unit of an element that has all of the properties of that element containing a nucleus within an electron cloud 2012 Rice University All Rights Reserved
Chemical Formula a single molecule of water a single molecule of glucose C 6 H 12 O 6 Key: Black = Carbon atoms Red = Oxygen atoms White = Hydrogen atoms Key: Red = Oxygen atom White = Hydrogen atom A shorthand notation that uses chemical symbols and numbers as subscripts to represent the type and number of atoms that are present in the smallest unit of the substance