Periodic Table of Elements

Matter: Properties and Changes

Warm upInstructions:

1. Use the periodic table of elements to looks for the letters in your first or last name to write your name in elements.

2. Draw a square for each element your are going to use.3. Write the element symbol in the center, add the atomic number in the top

right, and write the name of the element below the element symbol.4. If the letter isn’t in the periodic table just write the letter.

Review● Elements:

○ one of the basic substances that combine to form all other substances○ cannot be broken down into simpler substances by ordinary chemical means○ Scientists have discovered about 118 elements.

● Atoms:○ is the smallest particles of an element that has all the properties of that element○ Each element is made up of atoms that differ from those of every other element.

History about Elements

● In 1869, a total of 63 elements had been discovered.● Dmitri Mendeleev discovered a set of pattern in the properties of the

elements.○ Example:

■ Silver and copper are both shiny metals that tarnish if exposed to air.

● He noticed that a pattern of properties appeared when he arranged the elements in order of increasing atomic mass.○ Atomic mass

■ is the average mass of all the isotopes of that elements■ is equal to the total mass of protons, neutrons, and electrons in the atom

Mendeleev’s Periodic Table● In 1869, Mendeleev published the first

periodic table.

● In this periodic table, the properties of

the elements repeat in each period, or

row, of the table.

● He left three blank spaces in the table.

He predict that this spaces would be

filled by elements that had not yet been

discovered and even predicted the

properties of those elements.

Modern Periodic Table● After protons were discovered , elements were rearranged according to

atomic number.● Some elements changed positions and the patterns of properties became

more regular. ● The modern periodic table contains over 100 squares, one of each element.● The periodic table is a chart that organizes information about the elements.● Each square includes the element’s atomic number, chemical symbol, name,

and atomic mass.

Finding Data on Elements ● Each element has a square that include:

○ atomic number○ chemical symbol○ name○ atomic mass

Finding Data on Elements● Atomic number is the number of

protons in the nucleus of an atom.● Chemical symbol for an element

usually consists of one or two letters. (iron - Fe)

● Average atomic mass (weight) is an average because most elements consist of a mixture of isotopes. ○ Isotopes are atoms with the same

number of protons and a different number of neutrons.

Organization of the Periodic Table● The properties of an element can be predicted from its location in the

periodic table. ● Each horizontal row of the table is called a period. As you move across a

period from left to right, the properties of elements change in a predictable pattern. There are seven periods of elements. (Left side - highly reactive metal, right side - unreactive gas)

Organization of the Periodic Table● The elements in a column are called a group, or family.● The group are numbered from Group 1 on the left to Group 18 on the right. ● The family name of a group is typically the name of the first element in the

column.● Elements in each group have similar characteristics. (metals react violently

with water are in one group)

Review - Classwork1. In what order did Mendeleev arrange the elements in the first periodic table?2. What pattern did Mendeleev discover when he arranged the elements?3. Describe two differences between Mendeleev’s periodic table and the modern

periodic table?4. List three kinds of information about an element that can be found in a

square of the periodic table?5. What element has 47 protons in its nucleus?6. Why aren’t the atomic masses of most elements whole numbers?7. What does an element’s location in the periodic table tell you about that

element?