Groups of Elements Additions to your periodic table

Groups of Elements: Additions to your periodic table Get out your periodic table if you didn’t catch that

1 18 Label Group #s 2 3 4 5 6 7 8 9 13 14 15 16 17 10 11 12

Hydrogen • Gas at room temp • 1 valence electron • Extremely reactive

1 18 Label Group #s 2 3 4 5 6 7 8 9 13 14 15 16 17 10 11 12

Alkali Metals • Group 1 • 1 valence electron very reactive (especially with water) • extremely reactive (especially with water) thus are never found as pure elements in nature • They are shiny, have the consistency of clay, and are easily cut with a knife.

Alkaline Earth Metals • Group 2 • They are never found uncombined in nature. • They have 2 valence electrons and are very reactive.

Transition Metals • Transition Elements include those elements in groups 3 -12; they have a variable number of valence electrons • These are the metals you are probably most familiar: copper, tin, zinc, iron, nickel, gold, silver, etc. • They are good conductors of heat and electricity.

Boron Group • named after the first element in the family. • Atoms in this family have 3 valence electrons. • This family includes a metalloid (boron), and the rest are metals. • This family includes the most abundant metal in the earth’s crust (aluminum).

Carbon Group • Atoms of this group have 4 valence electrons. • This group includes a non-metal (carbon), metalloids, and metals. They form special bonds because of the symmetry of 4 chemical bonds. • The element carbon is called the “basis of life. ” There is an entire branch of chemistry devoted to carbon compounds called organic chemistry.

Nitrogen Group • named after the element that makes up 78% of our atmosphere. • This group includes nonmetals, metalloids, and metals. • Atoms in the nitrogen family have 5 valence electrons. They tend to share electrons when they bond.

Oxygen Group • Atoms of this group have 6 valence electrons. • Most elements in this family share electrons when forming compounds. • Oxygen is the most abundant element in the earth’s crust. It is very reactive and combines with almost all elements.

Halogen Group • Halogens have 7 valence electrons, which explains why they are the most • Halogen atoms only need to reactive non-metals. gain 1 electron to fill their They are never found outermost energy level. free in nature. • They react with alkali metals to form salts.

Noble Gases • colorless gases that are extremely un-reactive. • One important property of the noble gases is their inactivity. They are inactive because their outermost energy level is full; they have all 8 valence electrons. • Because they do not readily combine with other elements to form compounds, the noble gases are called inert. • The family of noble gases includes helium, neon, argon, krypton, xenon, and radon. • All the noble gases are found in small amounts in the earth's atmosphere.

• The thirty rare earth Rare Earth Elements elements are composed of the lanthanide and actinide series. • One element of the lanthanide series and most of the elements in the actinide series are called trans-uranium, which means synthetic or man-made. • Most are radioactive!

Chemical Bonding Notes

Valence Electrons Valence electrons are the electrons which are on the highest energy shell of the atom, thus they are held more loosely. The number of valence electrons in an atom’s outer most shell determines how it forms chemical bonds with other atoms to form molecules and compounds Valence electrons can be shared or transferred to chemically bond atoms

The Octet Rule -simplified Elements want to fill their valence electron shells; most elements need 8 to fill the valence shell, thus the “Octet Rule”. *Hydrogen, Helium, Lithium , and beryllium need 2 Ve- to fill the valence shell

Covalent and Ionic Bonds

Chemical Bonding Examples Lithium and sodium commonly forms ionic bonds to chlorine or fluorine because the halogens need only 1 electron to complete their octet and the alkali metals only need to give away 1 to have a full valence shell. The non-metals typically form covalent bonds with each other, sometimes even sharing 2 or 3 electrons instead of 1.

The Law of Conservation of Matter cannot be created or destroyed, it only changes forms. What you put into a reaction, you must get back out of the reaction (in mass and atom #)