The Atom

What to look for:Three Essential Questions

E. Q. #1 = What are the parts of an atom? E. Q. #2 = In what manner can subatomic particles be differentiated?

E. Q. #3 = How does the atomic structure impact chemical change & reactivity?

The Building Block of Matter

400 BC Democritus (_______ Philosopher)Atomos = “_______________”…like a brick is used to build a __________; an

atom is used to build all matter…

First Atomic Theory

________ (yr) John Dalton (__________ Chemist)

Using experiments formulates the first ______________ theory

1. All elements are composed of indivisible particles called __________

2. ________ of the same elements are exactly the same3. ________ of different elements are different4. Two or more ______________ combine to form

compounds

Subatomic Particles

The idea that the ________ was not a solid sphere, but a composition of small particles which came to be known as ______________ ________________ (2 words)

Julius Plucker, William Crooks & J J Thomson

_________________

J J Thomson

• ________ Discovers the electron• First of the subatomic particles to be

discovered.

Ernest Rutherford (___________Physicist)

Gold Foil Experiments________ Discovers

that the atom is mostly empty space

Later, he discovers a hard, dense center of the atom called the ______________

The Gold Foil Experiment

The _______ is mostly empty space

Most of the _____________ passed straight through to gold foil.

First important discovery by Rutherford

The NUCLEUS is Discovered

_______ Rutherford proves that the particles that do not pass through are hitting a small, dense ______ of the atom called the nucleus.

____________ later goes on to discover the proton

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Name three major discoveries made by Ernest Rutherford & the Gold Foil Experiment:

1. _______________________________________

2. _______________________________________

3. _______________________________________What are the two results of firing particle at atoms in the foil of the Gold Foil Experiments:

1. _______________________________________

2. _______________________________________

Who was the first to attempt to form a complete atomic theory?

1. _______________________________________

Electron ____________ Levels

_______ Niels Bohr (_________ physicist) discovers the electrons travel around the outside of the atom on different energy levels

The Bohr Model = “solar ___________” model

The ___________ is Found

________ James Chadwick proves the existence of the neutron.

Only ______ years later the neutron is used to split the first atom

Why was the neutron’s existence more difficult to prove?

What evidence hinted of its existence? “the missing mass”

E. Q. #1 = What are the parts of an atom?

The Subatomic Particles

Particle Location Mass (AMU)

Charge

Electron

Proton

Neutron

E. Q. #2 = in what manner can subatomic particles be differentiated?

Finding the Number of _____________ Particles in an Atom

Atomic Number = the __________ of protons in the nucleus of an atom

Identifies each element____________ is #1 and it has 1 proton in its

nucleus (only hydrogen has 1 proton)____________ is #2 and it has ___ protons in

its nucleus (only helium has ____ protons)

# of Electrons

IF the atom is neutral (______ number positive charges as negative charges) then the number of electrons will be the same as protons.

ION = a charged atom (unequal number of protons and electrons)

+1 charge = the atom LOST ______ electron -1 charge = the atom GAINED _____ electron+2 charge = LOST _____ electrons -2 charge = GAINED ____ electrons and so on

Example of Ions

Sodium will lose _____ electron when it bondsNa+1 or Na+

Sodium’s atomic number is 11, so it has 11 ________________.

The +1 charge means Na+1 has ____ electrons

Another Example

Chlorine will gain an _______ when it bondsCl-1 or Cl-

Chlorine’s atomic number is 17, so it has 17 ____________

The -1 charge means Cl-1 has ____ electrons

________ Number

The _____ subatomic particles that have mass?

Proton ____ neutron, both found in the nucleusMass Number = # of Protons + # of Neutrons

Mass # - Atomic # = # of neutrons

Practice Problems

Symbol Atomic Number

Mass Number

Charge Protons Neutrons Electrons

Mg 12 24

K 19 39

Na+1 11 23

F-1 9 19

Mg+2 12 24

Do Parts of the Atom & Atomic Structure practice sheet now.

ISOTOPES

Atoms of the same element with a different number of neutrons.

Ex: carbon-12 & carbon-14 Carbon- ______

1. ___ protons2. ___ neutrons3. ___ electrons

Carbon- ______1. ___ protons2. ___ neutrons3. ___ electrons

Isotopes of Hydrogen

Hydrogen-1 (protium) 0 __________Hydrogen-2 (deuterium) 1 __________Hydrogen-3 (tritium) 2 __________

The ELECTRON ______________

The electron cloud is separated by different energy __________.

Electrons with less ________ travel on the levels closest to the nucleus.

Energy ________ are divided into sub-levelsSub-levels are divided into orbitalsAll of these _________, sub-levels & orbitals

can overlap.

VALENCE ELECTRONS

Valence electrons = the outermost electrons

The ___________ involved in bondingDetermines the _________ properties of

an atom

Do What Is This Atom Now? Practice sheets 1 & 2 now.

E. Q. #3 = How does the atomic structure impact chemical change & reactivity?

More about Electrons

Maximum # of electrons on each energy level

Level ____ = 2 electronsLevel ____ = 8 electronsLevel ____ = 18 electronsLevel ____ = 32 electrons

the Stable ______ Due to the overlapping levels, sub-levels and

orbitals the maximum number of outer most electrons is _____________.

An atom is becomes stable when it outer-most energy levels is ________ of electrons

This explains the chemical bonding properties of the _____________

_________ will do one of three things in order to fill their outer most energy levels.

1. gain electrons2. lose electrons3. share electrons

Concepts Coming Up Next

The number of valence electrons an atom has determines the group it becomes to on the _______________ _____________.

Groups or families of elements on the periodic table has similar ______________ properties.

Valence ____________ determine how atoms will bond with other atoms in order to complete their outer-most energy level.

The Stable ______ CHEMICAL _____________

Ionic bonding (gaining/losing of electrons) Covalent bonding (sharing of electrons)

Concepts Coming Up Next