 Dmitri Mendeleev, a Russian scientist born in Tobolsk, Siberia in 1834, is known as the father of the periodic table of the elements.  The periodic table of the elements is an important tool used by students and chemists around the world to help them understand and simplify the often complex world of chemical reactions.

 Mendeleev set out to find a pattern in the elements.  He wrote facts on paper cards for each element.  Melting Point  Density  Colors  Atomic Masses

 After laying all of his cards out he noticed that by arranging them according to their properties they were arranged in order of increasing atomic mass.  Mendeleev was even able to use the patterns in his table to predict the properties of undiscovered elements.  The first periodic table was published in 1869.

 Arrangement of the known elements based on atomic number and chemical and physical properties  Divided into three basic categories:  Metals  Non-Metals  Metalloids

The periodic table is useful in predicting:  Chemical behavior of the elements  Trends  Properties of the elements

 Atoms are made of protons, electrons, and neutrons.  Elements are atoms of only one type.  Elements are identified by the atomic number (# of protons in the nucleus).

 Electrons are arranged in a region around the nucleus called an electron cloud. Energy levels are located within the cloud.  At least one energy level and as many as seven energy levels exist in atoms.

 Electrons in levels farther away from the nucleus have more energy.  Inner levels will fill first before outer levels.

 Energy levels hold a specific amount of electrons:  1 st level = up to 2  2 nd level = up to 8  3 rd level = up to 8 (first 18 elements only)

 The electrons in the outermost level are called valence electrons.  Determine reactivity - how elements will react with others to form compounds  The outermost level does not usually fill completely with electrons.

 Elements are grouped into vertical columns because they have similar properties.  These are called groups or families.  Groups are numbered 1–18.

 Group numbers can help you determine the number of valence electrons:  Group 1 has 1 valence electron.  Group 2 has 2 valence electrons.  Groups 3–12 are transition metals and commonly have 1 or 2 valence electrons, but may have more.

 Groups 13–18 have 10 fewer than the group number. For example:  Group 13 has 3 valence electrons.  Group 15 has 5 valence electrons.  Group 18 has 8 valence electrons.

 Reactivity is a chemical property that determines how elements will react with others to form compounds.

 What makes an element reactive? ● Number of valence electrons each atom has ● When outer levels are full, atoms are stable. ● When they are not full, they react: ● Gain, lose, or share electrons

 The most reactive metals are the elements in Groups 1 and 2.  Elements in Group 1 need seven more electrons to fill their outer level.  Elements in Group 2 need six more electrons to fill their outer level.  These groups are known as the “givers” because they easily give up their valence electrons to make a compound.

 The most reactive nonmetals are the elements in Groups 16 and 17.  Elements in Group 16 only need two more electrons to fill their outer level.  Elements in Group 17 only need one more electron to fill their outer level.  These groups are known as the “takers” because they easily receive valence electrons to make a compound.

 Groups run vertically in the periodic table.  They are numbered from 1–18.  Elements in the same groups have the same number of valence electrons in the outer energy level with the exception of some transition metals.  Grouped elements behave chemically in similar ways.

 The Periodic table is designed to help you predict what an element's physical and chemical properties are.  You can also predict what elements will bond with each other.

Vertically into Groups Horizontally Into Periods

 An example…

Be (Beryllium) Atom Mg (Magnesium) Atom

 The number of outer or “valence” electrons in an atom effects the way an atom bonds.  The way an atom bonds determines many properties of the element.  This is why elements within a group usually have similar properties.

you would see…

An example…

K (Potassium) Atom Fe (Iron) Atom Kr (Krypton) Atom 4 th Shell

 The periodic Table is divided into several groups based on the properties of different atoms.

Families/Groups on the Periodic Table Elements on the periodic table can be organized into families or groups based on their physical and chemical properties. Each family/group has a specific name to differentiate it from the other families/groups in the periodic table. Elements in each family/group react differently with other elements.

Fill in the notes as we go thru…. Color code each small section so that you will know how to color/label the ‘big’ Periodic table.

HYDROGEN Stands alone 1 valence electron Very reactive Reacts violently with Oxygen under right conditions

ALKALI METALS Group 1 Hydrogen is not a member, it is a non-metal. 1 valence electron in its outermost shell Soft and silvery metals Very reactive, esp. with water and the halogens (group 17 with 7 valence electrons) Conduct electricity Image:

ALKALINE EARTH METALS Group 2 2 valence electrons in the outermost shell White and malleable metals Reactive, but less than Alkali metals Conduct electricity

TRANSITION METALS Groups 3-12 in the middle The number of valence electrons is varied in the transition metal groups. Less reactive than the first two groups. Can bond with many elements in a variety of shapes. Good conductors of heat and electricity. Some are used for jewelry.

METALLOIDS A zig-zag line that separates metals from metalloids— Outline the metalloid element boxes darkly A zig-zag line that separates metals from metalloids— Outline the metalloid element boxes darkly Elements from Groups 13–17 contain some metalloids. Elements from Groups 13–17 contain some metalloids. These elements have characteristics of metals and non-metals. These elements have characteristics of metals and non-metals.

BORON FAMILY Group 13 3 valence electrons in the outermost shell Most are metals Boron is a metalloid Mildly reactive; need to lose three electrons or gain five electrons to be stable. Aluminum is the 3 rd most common element in the Earth’s crust Increase in reactivity as the atomic number increases (move down).

CARBON FAMILY Group 14 4 valence electrons in the outermost shell Contains metals (Sn, Pb), metalloids (Si, Ge), and a non-metal Carbon (C) Mildly reactive; need to lose or gain four electrons to be stable. Sometimes found bound to itself such as in diamonds, tin cans, lead pipes. Carbon is found in all organic matter.

NITROGEN FAMILY Group 15 5 valence electrons in the outermost shell Mildly reactive Can share electrons to form compounds. Needs to lose five electrons or gain three electrons to be stable. Contains one metal (Bi), metalloids (As, Sb), and non-metals (N).

OXYGEN FAMILY Group 16 6 valence electrons in the outermost shell Contains metalloids (Te, Po) and non-metals (O, S, Se) Reactive, but less than the Halogens (group 17) Oxygen is the most common element found in the Earth’s crust and as O 2 is needed for us to breathe.

HALOGENS Group 17 7 valence electrons in the outermost shell All are non-metals Very reactive and are often bonded with elements from the Alkali Metals (Group 1) Also known as ‘salt- formers’ because they form salts when they react with metals.

NOBLE GASES Group 18 Non-metals 8 valence electrons in the outer shell = Stable Helium (He) has only 2 electrons in the outer shell = Stable Not reactive with other elements Exist as gases

Lanthanides and Actinides (Rare Earth Metals) Some are Radioactive (give off radiation) Some rare earths are silver, silvery- white, or gray metals. Conduct electricity