What good is the Periodic Table?

A Periodic Table is provided for your use during the TAKS test. What can it do to help you?

What is an element?

• Basically, if it is listed anywhere on the periodic table, it is an element.

• If it is on the left side it is a metal element.• If it is on the right side it is a NONmetal element.

• Hydrogen is the ONLY nonmetal to the left of the stairstep line.

• Let’s look . . .

Where are the metal elements?

To the Left of the Stair-step line!

Where are the nonmetals? To the Right of the stair step line, including

Hydrogen!

Where are the metalloids?

Along the stair step line.

These elements have properties of both metals and nonmetals.

The center elements on the table are called the transition metals. Many of them have more than 1 way they will give away electrons, so they change, or transition, ion charges. The charge these metals use are given by a

roman numeral in the compound name. (Iron (II) chloride)

The Rare Earth Metals are radioactive and form the bottom 2 rows, also called the Lanthanide and Actinide Series.

Now, I can tell if it’s a metal or not. What else do I need to know?

• Each column on the table is a group or family of elements that have similar chemical properties.

• They form the same types of compounds, in the same ratio.

• They have the SAME NUMBER OF OUTER SHELL (valence) electrons.

• Lets look . . .

Group # 18 is the family called Noble Gases – each one has 8 outer shell

electrons (full shell) so they don’t form compounds.

Group #1 is called the Alkalai metals, they have 1 valence electron, and will form +1

ions. The are Alkalai because they form the strongest (highest pH) bases.

Group #2 is called the Alkalai Earth Metals and they have 2 valence

electrons, which they will give away to form +2 ions.

Group #17 are the Halogens, they all have 7 electrons in their valence shell,

and want to have 1 more when they form compounds. They all become -1 ions

when they can.

Each group forms compounds the same way, for example. . .

• Beryllium forms a compound with Cl in the ratio of 1:2 or BeCl2

• Since Mg and Ca are in the same family or group, they will form the same type of compounds in the same ratio.

• MgCl2 and CaCl2 • This is what is meant when they have “similar chemical properties.”

Each square also tells us information about each element.• The 1 or 2 letters

that represent the element are its symbol.

• The number at the top of the square is the atomic number.

• The numbers at the bottom of the square is the average atomic mass.

What do the numbers mean?

Na

11

22.990

sodium

This is the atomic number. It is the

number of protons in a single atom of this

element. By the way, its also # of electrons

in a neutral atom. This is the symbol for this element.

The atomic mass is the number of protons PLUS the number of neutrons, or the

average mass of ALL sodium isotopes. An isotope has the same atomic number but a

different atomic mass because the isotope has a

different number of neutrons.

This is the name of the element.

Use the table, it will help you answer at least 5 questions!

It may be the difference you need to pass!!

Now, let’s write some formulas and names… 1. Elements from opposite sides of the Periodic

Table will form IONIC bonds (opposite sides = opposite charges).

2. Elements from the Non-metals will form COVALENT bonds.

3. The + ion (from the Left side) is ALWAYS written first and followed by the – ion (from the Right side).

4. When the ions have different charge numbers (Na+1 & O-2), use the charge number as the subscript for the opposite ion, but remove the sign (Na2O) (sodium oxide).

5. Polyatomic ions include NH4+1 & PO4

-3. When writing them in a formula, the charge is written as a subscript outside the ( ) (NH4)3PO4…ammonium phosphate.

6. To name the compound, write the name of the + ion first, then the name of the – ion, and change the ending to –ide for elements & -ate/-ite when O is present in a polyatomic ion PO4

-3 (phosphate). 7. Transition metals use a Roman Numeral in

their names for their charge. Copper (l) chloride = Copper (l) = (Cu+1) chloride (Cl-) = (CuCl). Copper (ll) chloride = Copper (ll) = (Cu+2) chloride (Cl-) (CuCl2).

Law of Conservation of Mass

• Matter can not be created or destroyed.

• This means if it is on one side of an equation, it must be on the other, and there must be the same number of atoms of that element.

Thanks for participating . . .

Remember…it’s all elemental!!!