Element Families

Now that you've completed you Periodic Table books, check to make sure you included some of these main ideas on each of your pages.

Element Square - The four things included in the element square are atomic number, atomic mass, element symbol and the element name.  Remember, the atomic number comes from the number of protons in the nucleus.  The atomic mass is found by adding the protons and neutrons together.  When writing the element symbol, the first letter is always capitalized.  If there is a second letter, is is lower case.

Valence Electrons - These are the electrons in the outer most energy level of an atom.  The number of valence electrons in an element can be determined by its position on the periodic table.  Every element in group one has one valence electron, group two has two and so on.  The number of valence electrons is important because it determines the properties of that element and how it reacts with other atoms.

*Hydrogen - This element does not match the properties of any other group so it stands alone. It is placed above group 1 but it is not part of that group. It is a very reactive, colorless, odorless gas at room temperature. (1 valence electron)

Alkali Metals – These metals are extremely reactive and are never found in nature in their pure form. They are silver colored and shiny. Their density is extremely low so that they are soft enough to be cut with a knife. (1 valence electron)

Alkaline-earth Metals – Slightly less reactive than alkali metals. They are silver colored and more dense than alkali metals. (2 valence electrons)

*Transition Metals – These metals have a moderate range of reactivity and a wide range of properties. In general, they are shiny and good conductors of heat and electricity. They also have higher densities and melting points than groups 1 & 2. (1 or 2 valence electrons)

Boron Group – Contains one metalloid and 4 metals. Reactive. Aluminum is in this group. It is also the most abundant metal in the earth’s crust. (3 valence electrons)

Carbon Group – Contains on nonmetal, two metalloids, and two metals. Varied reactivity. (4 valence electrons)

Nitrogen Group – Contains two nonmetals, two metalloids, and one metal. Varied reactivity. (5 valence electrons)

Oxygen Group – Contains three nonmetals, one metalloid, and one metal. Reactive group. (6 valence electrons)

Halogens – All nonmetals. Very reactive. Poor conductors of heat and electricity. Tend to form salts with metals. Ex. NaCl: sodium chloride also known as “table salt”. (7 valence electrons)

Noble Gases – Unreactive nonmetals. All are colorless, odorless gases at room temperature. All found in earth’s atmosphere in small amounts. (8 valence electrons)

*Hydrogen and Transition Metals were not pages in your books, but you should still understand the important characteristics of those two groups.

Finally, here is a link to today's activity; Martian Periodic Table