ATOMS*

History*of the Atom

Many ancient Indian/Greek philosophers had ideas about tiny particles

1661 Robert Boyle “matter is composed of various combinations of atoms instead of the 4 classical elements.” (Earth, Wind, Fire, Water.)

Atoms- General info

All matter is made up of atoms

Atoms cannot be divided or broken down using chemicals

Atoms are very small.

Atoms- General Info cont.

Most of the mass of an atom is made up of the nucleus (protons/neutrons)

Most of the volume of an atom is made up through the electrons.

Atoms are held together by very strong forces called bonds.

Structure* of the Atom

Protons/Neutrons- larger than electrons

Protons (+) charge Neutrons (0 neutral) charge Electrons (-) charge Electrons orbit around the

nucleus of the atom

Atomic Number

Atomic Number is the element # and is also the # of protons.

Ions and Isotopes

If the number of electrons changes in an element it is an ion.

Ions and Isotopes are the various forms than an element can come in.

Ions and Isotopes

If the number of neutrons changes it is called an isotope.

Carbon is an element that comes in many formshttp://www.youtube.com/watch?v=GsJPxR6IfZI

Radioactive isotopes

Some isotopes lose neutrons making them “unstable.”

As these isotopes lost neutrons they give off energy in the form of radioactivity.http://www.youtube.com/watch?v=cKJMk2Oiod0

*THE MODERN PERIODIC TABLEObj: Students will be able to explain the

three classifications of elements and the approximate number of them on the Periodic Table.

Periodic Table

The Modern Periodic Table

Arranged by increasing atomic # (# of protons)

Also arranged by number of available orbitals per energy level (rows)-periods.

*Mendeleev was not aware that elements have different numbers of protons.

www.ptable.com

Periods/Rows

Organized by energy levels available.

Lightest--Heaviest elements (atomic mass)

Groups/Families

Each column on the periodic table Elements in a group all have similar

properties Properties of elements repeat

predictably when atomic number is used to arrange groups (periodic law)

Similar electron configurations All have the same number of

valence e-

Assignment

Complete the table below using a periodic table for elements # 1-10

Element name

Symbol Atomic #/# of Protons

Atomic Mass

# of neutrons (atomic mass (rounded-atomic #)

# of electrons

Hydrogen H 1 1.00 0 1

*Beautiful Elements

Available Orbitals

Energy Level

Electrons

1 2

2 8

3 18

4 32

Valence Electrons

Valence electrons are the electrons that are in the outermost energy level of an atom

The number of valence electrons an element has will determine how an element chemically will bond with other elements

www.ptable.com

Assign

Practice chemical bonding and identifying valence electrons.

You will need 2 different colors.

Compounds

Substance formed chemically by two or more elements.

*CHEMICAL BONDSForces that holds atoms or ions together.

Electron Configurations

It all goes back to the periodic table… 1. Valence electrons determine how an

element will bond with other elements. a. highest energy level of an atom either

gains or loses electron.

Electron Configurations

-b. elements are trying to achieve stable 8 configuration by gaining or losing electrons

c. groups 1,2,13,14 all lose an electron, groups 14-17 all gain electrons.

*Formation of Ions

Formation of Ions a. elements that do not have 8 valence

electrons react easily. b. reaction and bonding allows the

elements to achieve stable electron configurations.

c. when an atom gains or loses an electron the number of protons/electrons is no longer equal. i. atoms that are positive or negative are

called ions and are represented by a positive or negative sign (-) or (+)

e. negative charge is called an anion f. positive charge is called a cation

Ionic Bonds- Electron Transfer Ionic Bond (remember

that positive and negative particles attract each other)

a. when cations and anions are in close proximity a chemical bond forms between the two atoms.

b. an ionic bond is a force that holds

cations and anions together.

c. forms when electrons

are transferred between atoms.

http://vimeo.com/7822850

*Covalent Bonds- Shared Electrons Covalent Bond A chemical bond in

which two atoms share a pair of valence electrons. a single bond is a bond

in which two atoms share one pair of electrons.

attraction of shared electrons and protons in each nucleus hold atoms together in covalent bonds.

Forms between atoms that are non-metals

Bonding

Assign

Chemical bonding cartoon (due Monday)

Chemical bonding

Ionic bonding- electrons are lost/gained (transferred) to other atoms. When an atom is lost it receives a positive + charge and is called a cation. When an atom is gained it receives a negative charge – and is called an anion.

Covalent bonding- electrons are shared with other atoms