Periodic TableBasic Structure

Rows and Columns The Periodic Table

has • 7 rows called

“Periods” – 1-7• 18 columns called

“Groups” – 1-18

Element Arrangement Elements are ordered from left to

right, top to bottom by increasing atomic number

Atomic numbers are 1-118

Common Properties Elements in each column, or group,

have common chemical properties• Example: all elements in Group 18 are

gases.• The collective name for this group of

elements is the “Nobel Gases”• Other groups have names as well

Lots of Information The Periodic Table can give us lots of

information about the atoms of each type of element

Chemical Symbol Each element (kind of atom) has a

unique chemical symbol. This is used as a short way of writing

the names of elements These symbols are also used when

writing chemical equations Each chemical symbol is made up of

1-3 letters

Examples of Chemical Symbols

Chemical Symbols Cont’d The first letter of each chemical

symbol is ALWAYS CAPITALIZED. All other letters in the symbol are

lowercase Writing chemical symbols properly is very important in chemistry.

Capitalizing the wrong letter may indicate a different element.

Examples of Improper Capitalization of Chemical Symbols

Cl = Chlorine (correct) CI = Carbon and Iodine (incorrect)

Co = Cobalt (correct) CO = Carbon Monoxide (incorrect)

Si = Silicon (correct) SI = Sulfur and Iodine (incorrect)

# Protons The difference

among all atoms is the number of protons it has

The smallest atom has 1 proton

The largest atom has 118 protons

Atomic Number This indicates the number of protons

in each atom of a particular element. This number is usually in the largest

font in each box. Notice that atomic numbers increase

as you look left to right across the Periodic Table

Examples of Atomic Numbers

Importance of Atomic Number

The identity of an atom is determined by it’s atomic number

Knowing the atomic number of an element can help you draw an electrically neutral atom for that element