The Periodic Table!  Mr. Coffey

The Periodic Table of Elements Used to keep track of the different elements that are natural & man made developed by Dmitri Mendeleev Mendeleev used atomic mass. The modern Periodic Table uses atomic number

# of protons = atomic number Organization The elements are arranged by increasing atomic number! (They count up in order!) Remember atomic number is the same thing as the number of protons The layout of the table (where things are located) is important; the position of things tells us information about specific elements. # of protons = atomic number

Parts to Know: Atomic Number: tells us number of protons in an atom The number of protons and the number of electrons in an atom are always the same We always assume that atoms are neutral The atomic number is specific to each element, like our DNA or fingerprints. We can change the number, but doing so changes the element we have! Proton = (+) charge Electron = (-) charge +6 plus -6 = 0 0 means neutral charge overall

Review of each “box” 17 p 18 n Three shells: 1st shell has 2 electrons 2nd shell has 8 electrons 3rd shell has 7 electrons Mass # Symbol Atomic # Order of electrons # Protons = 17 # Electrons = 17 # Neutrons = 35 – 17 = 18 17 p 18 n

…more parts… Chemical Symbol: letters that are used to represent the names of different elements The first letter is always upper case and the second letter is always lower case Ex: Chlorine is always Cl Mass # Symbol Atomic # Order of electrons Al the symbol for Aluminum. Its atomic # is 13. This means it has 13 protons. Its mass is 27.

Valence Electrons Valence electrons are the electrons located in the LAST energy shell of an atom. It is important because it determines how it reacts with other atoms. 11

Example: Valence Electrons # Shells How many valence electrons 2 2 3 3 3 3 1 2 5 6 7 8

Families or Groups There are columns on the periodic table called families or groups. Each family/group is named and they tell us the number of valence electrons an atom has. Just like our families, elements in the same family/group have a lot in common. Group 17 are used as cleaning products

Electron Configuration The bottom of each elemental box has the electron configuration. It tells you how many energy shells it has and how many electrons go in each shell. Remember: the last number tells you the number of valence electrons. Families/Groups (usually) have the same number of valence electrons! This is the electron configuration. There are 4 energy shells and the number of valence electrons is 2.

Rings = shells = energy levels Rows! There are 7 rows on the periodic table, they tell us the number of RINGS an atom has. Rings = shells = energy levels

Row is the same thing as period number!

Metals Metals constitute most of the Periodic Table. They are on the LEFT of the staircase Properties of metals: Malleable (can be hammered) Ductile (can be drawn into a wire) Has luster (shiny) Good conductors of heat and electricity

Nonmetals SULFUR Nonmetals are located to the RIGHT of the staircase. Properties of nonmetals: Dull Poor conductors of heat and electricity A lot of nonmetals are gasses at room temperature NOT malleable and NOT ductile Brittle (easily smashed into a powder) SULFUR

Metalloids Metalloids are in between metals and nonmetals and are on the staircase. Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), and Tellurium (Te) Properties of metalloids: They are semiconductors They have some properties of metals They have some properties of nonmetals Ex: Te is shiny AND brittle Antimony

Family 1 / Group 1 These are called the Alkali Metals. Highly reactive, shiny, color of silver, and very soft Since they are in Group 1, they have 1 valence electron.

Family 2 / Group 2 These are called the Alkaline Earth Metals. Since they are in Family 2, they have 2 valence electrons. They are reactive metals, the color of silver, and are denser than group 1.

Transition Metals Families 3-12 are transition metals because they are transitioning from metals to nonmetals. Their valence electrons vary They are usually very colorful when combined in compounds, like CuSO4.

Families/Groups 13-16 Key: Nonmetals Metals Metalloids They have metals, nonmetals, and metalloids. They have a different number of valence electrons. Key: Nonmetals Metals Metalloids

Family 17 / Group 17 These are called the Halogens. They are all nonmetals. They are very reactive and are poor conductors of electricity They usually combine with group 1 to make salts F

Family 18 / Group 18 These are called the Noble Gasses. They are all nonmetals They are unreactive, colorless, odorless gasses at room temperature.

The extra 2 periods The extra 2 rows are called the Lanthanides and Actinides and are there for a reason! If they were placed where they belong they would push the elements in the respective rows/periods OUT of the correct columns! Also, their placement would put them in Transition Metals; which means their location is more or less irrelevant, while the placement of elements in Families/Groups 13-18 is significant. Lanthanides Actinides