The Periodic Table

• Atomic number- tells the number of protons, electrons and the location of the element on the Periodic Table

• Atomic Mass- the sum of the protons and neutrons in the nucleus of the atom

• To find the number of neutrons, subtract the atomic number from the atomic mass

• APE MAN

Electron Shell Rules:

1st shell can hold up to 2 electrons

2nd shell can hold up to 8 electrons

3rd shell can hold up to 18 electrons

• The periodic table is divided into 3 types of chemicals

• They are in alphabetical order: 1. Metal, 2. Metalloid, 3. Nonmetal

• Metals are the largest group

• Metalloids are the smallest group between metals and nonmetals.

• Metals – Shiny, lustrous, ductile and malleable, and very good conductors of heat and electricity.  Usually solid.

• Metalloids – Shiny, brittle and a fair conductor of heat and electricity.

• Nonmetals – Dull, brittle, poor conductors of heat and electricity.  Usually liquid and gas.

• Represented by the symbol H and the electron configuration 1s1.

• A colorless, odorless, tasteless gas.

• Hydrogen forms more compounds than any other element. Most abundant element in the universe.

• Very little free H in the earth’s atmosphere. It is a diatomic gas; H₂

• Has the lowest density of ALL gases at room temperature and pressure.

• It is flammable.

• Li, Na, K, Rb, Cs, and Fr (Notice H is NOT a Alkali metal)

• Do NOT occur in nature as elements.

• Usually a white salt compound

• Are very reactive metals (Very reactive with H₂O)

• 1 valence e-

• Forms 1+ ions

• Are good conductors of heat and electricity.

• Are ductile, malleable and are soft enough to be cut with a knife.

• Have a silvery luster

• Low density

• Low melting/boiling point

• Be, Mg, Ca, Sr, Ba, and Ra

• Do NOT occur naturally in their elemental state. - Usually a salt

• Are less reactive than alkali metals.

• Are good conductors of heat and electricity, ductile are malleable and have silvery luster

• 2 valence e-

• Forms 2+ ions

• Consist of metals

• Valence e- not predictable so no predictable charges for ions.

• Usually harder and more brittle than metals in groups 1 & 2

• Have higher m.p. and b.p. than metals in groups 1 & 2

• Are malleable and ductile

• Have silvery luster, except copper & gold

• Lanthanides: Shiny, silvery metals similar in reactivity to group 2.

• Actinides: All radioactive, Three were found on earth, the rest were man-made.

• F, Cl, Br, I and At

• Are all nonmetals

• Are found in the rocks of Earth’s crust and dissolved in sea water.

• Exist at room temp as a gas (F₂ & Cl₂), a liquid (Br₂) and a solid (I₂ & At). - Most are diatomic

• Are highly reactive

• Have 7 valence e-

• Forms 1- ions

• All elements in the group are gases: He, Ne, Ar, Kr, Xe, Rn.

• Found in minute quantities in the atmosphere. 

• Helium can be obtained from natural gas wells where it has accumulated as a result of radioactive decay.

• 8 valence electrons

• Do not form ions

• All gases & are monatomic.

• Originally named the “inert gases”, b/c it was thought they formed no compounds.

• Generally considered to be unreactive, b/c they have “closed-shell” configurations.

• Krypton reacts with Fluorine to form KrF₂

• Xenon forms a wide range of compounds w/ O₂ and F.

Atomic Number: Tells you the amount of protons in the atom and usually identifies the element. (located at the top)

Chemical symbol: An abbreviation or short representation of the name of a chemical element. Usually consists of one or two letters (the first one being capitalized.)

Chemical name (the element): the name of the element.

Atomic mass: The total weight of an atom. (on the bottom)