Atoms

Inside The Atom

Atoms

Atoms are the smallest particles of all matter.Matter is anything that takes up space and

volume.Atoms consists of 3 subatomic particles with

different charges.Protons are positiveNeutrons are neutral (no charge)Electrons are negative

Scientist and The Atom

The idea of atoms didn’t appear over night. It has evolved as scientist conduct new

experiments with new technology.Three very important scientist have helped build

the idea of the atoms and what they look like.John Dalton, J.J. Thompson and Rutherford

John Dalton

John Dalton (1844), an English school teacher, chemist, meteorologist and physicist.

Modern Atomic Theory 1) Matter is made up of atoms2) Atoms cannot be divided into smaller pieces3) All the atoms of an element are exactly alike4) Different elements are made of different

kinds of atom.

J.J. Thomson

J.J. Thomson, an English physicist, in 1897 created some test to figure out what an atom

He discovered the electron based on his experiments and research.

The electron is the negative charge particle that surrounds the nucleus.

Ernest Rutherford

Ernest Rutherford created experiments to learn what the atom looked like a couple of years

later. • He discovered that the atom had a nucleus.• The nucleus of the atom is where the proton

and neutron are located.

Atoms, matter and elementsAtoms have different parts.

The center of the atom is called the nucleus.Located in the center are protons and neutrons.

Surrounding the nucleus are electrons.

Models of the atomModels of the atom

A model is a small version of something larger

Electron “cloud”

nucleus

Neutrons and Protons

Electrons

John Daltons Model of the Atom

He thought an atom looked like a hard sphere that was the same through out, like a tiny

marble.

J.J. Thomson’s Model of the Atom

Thomson revised Dalton’s model and believed the atom was a sphere with evenly spread

negative and positive charges.

Electron Cloud ModelFew years later, a new model was created.

The electron cloud model is the current model of the atom.

• Electron cloud is a region surrounding the nucleus in which electrons travel in.

It contains a nucleus at the center with a electron cloud surrounding it.

Electron Cloud

Atoms create ElementsAtoms of the same kind create elements.

The different numbers of protons, neutrons and electron specify the type of element it creates.

In order to organize all the elements the periodic table was created.

Periodic TableDifferent elements have different kinds of atoms

with different atomic numbers.

Dmitri Mendeleev arranged the elements in order of their atomic number from smallest to largest in what is now known as the Periodic

Table of Elements.

Periodic Table

Atomic Mass and Mass Number

Atoms have an atomic number and a mass number.

• The atomic number of an atom is the number of protons found in the nucleus. – The # of protons usually equals the # of electrons

in an atom • The mass number is the number of protons

plus the number of neutrons found in the nucleus of an atom.

Atomic mass and Mass numberAtomic mass Helium atomIs the numberOf protons inThe nucleus ofAn atom.

Mass number is the number of protons and neutrons in the nucleus.

Protons

Electrons

Electrons

Helium Atom in The Periodic Table

2HE

Helium4.002

Atomic Number

Symbol

Full Name

Mass Number

Periodic Table

Each element is arrange in the periodic table by the number of protons it contains in its

nucleus.Beginning with the smallest number and ending

with the largest number.• Hydrogen has 1 proton.• Ununoctium has 118 protons.

Take out a sheet of paper

• THIS IS TO TURN IN!– Please write the FULL name of the element, what

the atomic number is, the atomic mass is and how many protons in the nucleus for:

–H, HE, Mn, Kr, Au, Ag, Xe, K, Na, Ne

Classification of elements

• Metals:– Usually shinny– Good conductors of electricity– Nearly all solid at room temperature– Malleable (bent easily)– Ductile (pulled into wires without breaking)

• Metals:– Usually shinny– Good conductors of electricity– Nearly all solid at room temperature– Malleable (bent easily)– Ductile (pulled into wires without breaking)

• Usually dull in appearance• Poor conductors of electricity• Many are gasses• Solids break easily and cannot change shape easily• Except for hydrogen all are found on the right side

of the periodic table

• Usually dull in appearance• Poor conductors of electricity• Many are gasses• Solids break easily and cannot change shape easily• Except for hydrogen all are found on the right side

of the periodic table

NonmetalsNonmetals

• Have characteristics of nonmetals and metals

• Not as good conductors as metals but better than non-metals

• All are solids

• Have characteristics of nonmetals and metals

• Not as good conductors as metals but better than non-metals

• All are solids

Metalloids

AtomsMost atoms have the same number of protons,

neutrons and electrons.• Helium has 2 proton, 2 neutron and 2

electron.• However some atoms don’t have the same

number of protons, neutrons or electrons.• These atoms are called isotopes and ions.

IsotopesAn isotope is an atom of an element that has the

same number of protons but different number of neutrons.

An isotope is a heavier atom. Not all elements have isotopes.

Carbon

Carbon is an element that has different isotopes.This means that all of carbon’s atoms have the same number of protons but different number

of neutrons.This results in heavier and lighter versions of the

element carbon.

Carbon Isotopes

Carbon 11 has 5 neutrons and 6 protons.

Carbon 12 has 6 neutrons and 6 protons.

Carbon 13 has 7 neutrons and 6 protons.

Carbon 14 has 8 neutrons and 6 protons.

Ions

An ion is an atom that does not have the same number of protons and electron.

This gives that atom a negative or positive overall charge because of the unbalance

number.

IonsWhen an atom has more protons that

electrons it has a positive charge because protons are positive.

When an atom has more electrons that protons it has a negative charge because

electrons are negative.

How an atom becomes an ION

An atom becomes an ion when it loses or gains an electron or a proton.

This process can occur when the atoms transfer electrons or protons to create new

substances.

Chemical Bonding

Atoms are the smallest pieces of all matter. When atoms bond together they form new

substances and create complex things.

Things like water and table salt exist because atoms of two different elements bonded

together.

BondingAtoms bond when the outer electrons, called

valence electrons, are shared or when they lose electrons.

Most atoms will have the same number of protons and electrons.

o Helium has an atomic number of 2 (2 protons)o Helium has the same number of electrons, 2.o The valence electron is the outer electron in

the Helium atom.

Chemical Bonds

There are different types of bonding.

Covalent bonds

Ionic bonds• Metallic bond • Non metallic bond

Covalent bondA covalent bond is when atoms share electrons

from their outer shell (orbit)These bonds are considered strong bonds and

create molecules.H2O is 2 hydrogen atoms bonded to 1 oxygen atom

by it’s electrons, this creates water.

Ionic bond

Ionic bond refers to the bonding between a metal and a metaloid ion.

This type of bond loses electrons instead of sharing electrons.

Ex. Metal reacts with oxygenTo create rust.

Review!Atomic mass Helium atomIs the numberOf protons inThe nucleus ofAn atom.

Mass number is the number of protons and neutrons in the nucleus.

Protons

Electrons

Electrons

Review! Atomic Structure

Protons and Neutrons are located in the nucleus.

The nucleus is the center of the atom.Electrons surround the center in the electron

cloud.The electron cloud is a series of orbits with different number of electrons depending on

the atom.

Atomic Structure review

Atomic structure of a helium atom atomic structure of an oxygen atom

Review! Electron Cloud Orbits

1st orbit 2 electrons only2nd orbit 6 electrons3rd orbit 10 electrons

REVIEW!

Isotopes are atoms of an element with different number of neutrons.

An ion is an atom of an element that will have a positive or negative charge because it will lose or gain electrons or protons!

Review

Two types of chemical bonding.

Covalent – bonding of outer electrons

Ionic – Bonding between metalloids and metals