IPC 03A Atoms & Elements

Atomic Structure History:

John DaltonDalton’s Atomic Theory:

• Proposed that elements are _____________________________identical, indivisible particles called ___________________.

• The name “atom” comes from

J.J. Thomson“Plum Pudding” Model

He said the atom had _____________ (raisins) immersed in a sea of ______________ ____________________(pudding).

J.J Thomson’s Cathode Ray Tube Experiment:

• He concluded that the _________________ were made up of very small _______________ charged particles, which he named __________

Ernest Rutherford“Gold Foil” Experiment

Discovered the ________________________ and that the atom is mostly _____________.

Rutherford’s Expectation(assuming the plum pudding model)

• Rutherford expected ______ ______________ particles to go ______________ the atom like in this picture.

Rutherford’s Actual Results• Instead, Rutherford

observed that some of the __________ particles bounced _____________; thus, he concluded there was a ________________ ____________________ nucleus.

Niels Bohr“___________________”

of the Atom

• Nucleus is in the __________.

• Electrons orbit the ____________.

Erwin Schrodinger“_______________________”

• The ___________ represents the probable ______________ of an __________.

James ChadwickDiscovered the ____________

• There was still __________ _____________ from the atom.

• Chadwick solved the problem by discovering the final subatomic particle, the __________________.

Jimmy Neutron

Exposing Scientist’s Contributions

Atomic Theory

John Dalton J.J. Thompson Rutherford J. Chadwick Niels Bohr Schrodinger

Atoms consist of three main Subatomic Particles

Atomic mass unit (amu) = ___________ the mass of a __________________________.

Protonsp+

Electronse-

Neutronsn0

Mass

Charge

Structure of The Atom

____________ is small, dense, and _______ ____________ charged.

___________ are located outside the nucleus in an ________ __________

Forces Within The Atom

• Electromagnetic Forces keep the electrons in _____________around the nucleus. The negatively charged _________________ are _____________ to the positively charged _____________ in the nucleus.

• Strong Nuclear Forces hold the _______________together by opposing the force of _____________ between the positive charged ____________ so the nucleus won’t break apart. Only acts on very short distances.

Chemical Symbols

• Elements are the simplest pure substance that _______________________ ____________________.

• Chemical symbols are an _________________ of the element’s name.

• The first letter is ALWAYS ____________ and the second letter is ALWAYS __________!

Element Symbol Origin

Copper Cu Cuprium

Gold Au Aurium

Iron Fe Ferrium

Lead Pb Plumbum

Potassium K Kalium

Silver Ag Argentum

Sodium Na Natrium

Tin Sn Stannum

An Element- contains one type of atom with a unique number of ______________________.

o The _________________ determines the element.o Ex: Carbon has ____ protons.

o If you _____________ the # of protons, you change the _____________________.o Ex: Nitrogen has ____ protons.

Neutral Atoms have the __________ # of electrons as protons. Ex: neutral Carbon has 6 ________ and 6 ________

Element Notation• Mass Number (M) –

–Found in the ______________ and makes of up _______ of the atom’s ___________ (99.99%).

• Atomic Number (A) - number of _____________________–Determines the ____________.

XM

A

Example: Carbon-12

1) What is the atomic number of Carbon?

2) What is the mass number of Carbon?

C12

6

IsotopesAtoms with the

Same _____________________(same atomic #) Different _______________________________ Different ______________________________

Sodium Isotopes

1) Atomic number?2) Mass number?3) No. of Neutrons?

4) Atomic number?5) Mass number?6) No of Neutrons?

Hydrogen Isotopes

• Hydrogen-1• (______________)

• Hydrogen-2• (_______________)

• Hydrogen-3• (______________)

Hydrogen IsotopesFill in the #protons, #electrons, & #neutrons:

Mass number No. of protons

No. of electrons

No. of neutrons

Hydrogen-1

Hydrogen-2

Hydrogen-3

Atomic Mass – is the _______________________ of all the element’s natural ________________The most common isotope will have a ________ __________________ of the atomic mass rounded to a ____________________number.

Atomic number =

Atomic Mass =The most common isotope of

silver is ______________.

Mendeleev’s Periodic Table

• Dimitri Mendeleev – organized information about all the known elements by

Groups & Periods

• Groups (Families) have similar properties and go down on the periodic table. There are

• Periods go across on the periodic table. There are

Identify the element in:

Group 2 (IIA), period 4

Group 17 (VIIA), period 5

Group 11, period 4

Look at the Periodic Table:

Metals, Nonmetals, & Metalloids

Properties of metals and nonmetals • Metalloids have

both metallic and nonmetallic characteristics –along the staircase.

• Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Astatine

Metals Nonmetals

Luster (shiny silver-gray, gold, copper)

___________________ (all different colors)

Malleable (hammered)

Ductile (drawn into thin wire)

__________Melting Points _________Melting Points

____________Conductors of heat & electricity

_________ Conductors of heat & electricity

________________ electrons ____________ electrons

Silicon is used in computer chips because conduct electricity (metals) yet insulate (nonmetals).

Energy Levels in an Atom

• Electrons occupy ________ around the _________.

• Each energy level can hold up to ____ electrons where n = the _____________

• The farther away an electron is, the higher the energy it possesses.

Electrons in Energy Levels

1. What is the most common isotope?

2. How many protons?

3. How many electrons?

4. How many neutrons?

5. How many electrons in the 1st energy level?

6. How many electrons in the 2nd energy level?

7. How many electrons in the 3rd energy level?

Cl35.45

17

Absorption of Energy

The __________________ absorbs enough __________________ causing the electron to be _________________ and “_____________” to a _____________________________energy level.

Emission of Energy• The electron

_______________when it falls back to its ___________ _______________ energy level (ground state) in the form of _________ ________________

Atomic Emission Spectrum (hydrogen)

Each line in the spectrum results from a different ____________ ____________

Emission Spectrum:

Iron (more e-)

Carbon (less e-)

Continuous Spectrum

Valence Electrons

• Electrons in the ________ energy level

• Electrons used to form ________ _______

Group # of Valence Electrons

1A (1)

2A (2)

3A (13)

4A (14)

5A (15)

6A (16)

7A (17)

8A (18)

Octet Rule• In order to become most _______, all atoms

need 8 valence electrons in the outermost energy level.

• ______ ______ already have 8 valence electrons which is why they are _______.

• Other elements _____ or _____ electrons by forming chemical bonds in order to have 8 ________ _______ in the outermost energy level.

Oxidation Numbers• _____ generally ____

electrons to become more stable.– ______ form ______

ions (charged atoms)

• _________ generally _____ electrons to become more stable.– _________ form

_______ ions (charged atoms)

Group Oxidation #

1A (1)

2A (2)

3A (13)

4A (14)

5A (15)

6A (16)

7A (17)

8A (18)