Transcript Slide 1

• Protons are in the nucleus
(center) of the atom
• Have a positive charge
• Neutrons are in the nucleus
(center) of the atom
• Are neutral; have no charge
• Electrons move in energy
levels outside of the nucleus
• Have a negative charge
• Nucleus contains both
protons and neutrons and
most of the atoms mass
• Have a positive charge
http://jchemed.chem.wisc.edu/JCESoft/CCA/pirelli/pages/cca3NI3.html
The columns are called groups or families. Groups have similar physical and
chemical properties and the same number of valence electrons
Name the groups boxed in yellow, orange, green and blue.
Name the groups boxed in yellow, orange, green and blue. Alkali metals, Alkaline
Earth metals, Halogens, and Noble or Inert Gases.
The rows are called periods. The period number matches the principle energy level
of the element. This will be the principle energy level of the valence electrons.
What is the principle energy level of Nickel, Ni?
What is the principle energy level of Nickel, Ni? 4—it is in the row numbered 4
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Click on the link to get the SOL periodic table
Keep this Adobe file open as you work on the review
Let’s use the periodic table to answer some questions about
Silicon
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have?
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have?
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have?
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have? 16 neutrons. Silicon-30 is
an isotope of Silicon. It has a mass number of 30. The mass number is
protons + neutrons.
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have? 16 neutrons. Silicon-30 is
an isotope of Silicon. It has a mass number of 30. The mass number is
protons + neutrons.
What is the molar mass of Silicon?
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have? 30 neutrons. Silicon-30 is
an isotope of Silicon. It has a mass number of 30. The mass number is
protons + neutrons.
What is the molar mass of Silicon? 28.0855 grams/mole (this is the
same as the atomic mass on the periodic table)
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have? 30 neutrons. Silicon-30 is
an isotope of Silicon. It has a mass number of 30. The mass number is
protons + neutrons.
What is the molar mass of Silicon? 28.0855 grams/mole (this is the
same as the atomic mass on the periodic table)
How many valence electrons does Silicon have?
Chemistry SOL Review—Atomic Structure
Using the SOL Periodic Table
Let’s use the periodic table to answer some questions about Silicon.
How many protons does Silicon have? 14 protons = atomic number.
How many electrons does neutral Silicon have? 14 electrons (#
electrons = # protons in neutral atoms)
How many neutrons does Silicon-30 have? 30 neutrons. Silicon-30 is
an isotope of Silicon. It has a mass number of 30. The mass number is
protons + neutrons.
What is the molar mass of Silicon? 28.0855 grams/mole (this is the
same as the atomic mass on the periodic table)
How many valence electrons does Silicon have? 4 valence electrons.
Look for electrons in the highest principle energy level.
Chemistry SOL Review—Atomic Structure
An s orbital holds 2
electrons w/ opposite spins
Chemistry SOL Review—Atomic Structure
Each p orbital holds 2ewith opposite spins
Chemistry SOL Review—Atomic Structure
Each d orbital holds 2ewith opposite spins
Chemistry SOL Review—Atomic Structure
The orbitals and the periodic table
The s
suborbital fills
Chemistry SOL Review—Atomic Structure
The orbitals and the periodic table
The p
suborbitals fill
Chemistry SOL Review—Atomic Structure
The orbitals and the periodic table
The d
suborbitals fill
Chemistry SOL Review—Atomic Structure
Valence electron configuration and the periodic table
All group 13 elements have the
valance electron configuration
ns2np1.and 3 valence electrons
Chemistry SOL Review—Atomic Structure
Valence electron configuration and the periodic table
All group 15 elements have the
valance electron configuration
ns2np3.and 5 valance electrons.
Chemistry SOL Review—Atomic Structure
Valence electron configuration and the periodic table
What is the valence configuration
of the halogens?
Chemistry SOL Review—Atomic Structure
Valence electron configuration and the periodic table
What is the valence configuration
of the halogens? ns2np5.
Chemistry SOL Review—Atomic Structure
Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.
Atomic Radius: the radius of an atom in picometers
First Ionization Energy: The energy needed to remove the first
valence electron from a gaseous atom.
Electronegativity: The tendency of an atom to attract electrons
to itself when chemically combined with another element.
Chemistry SOL Review—Atomic Structure
Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.
Atomic Radius: the radius of an atom in picometers
1
2
13
14
15
16
17
18
Chemistry SOL Review—Atomic Structure
Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.
First Ionization Energy: The energy needed to remove the first
valence electron from a gaseous atom.
Ionization energy
increases as you
move to higher
number groups.
Group 18 has the
highest 1st
ionization energy.
Ionization energy
decreases as you
move down the
periodic table.
Chemistry SOL Review—Atomic Structure
Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.
First Ionization Energy: The energy needed to remove the first
valence electron from a gaseous atom.
Chemistry SOL Review—Atomic Structure
Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.
Electronegativity: The tendency of an atom to attract electrons
to itself when chemically combined with another element.
The halogen group has the highest electronegativity of the families.
The first period has the highest electronegativity. Noble gases do not
have electronegativity as the valence shell is already full.
Anions, Cations, and Electron
Configuration
Cations form by losing valance
electrons to take on a noble gas
configuration (ns2np6)
Chemistry SOL Review—Atomic Structure
Anions, Cations, and Electron Configuration
Cations form by losing valance electrons to take on a noble gas
configuration (ns2np6)
So Li loses the 2s1 electron to form Li+1.
Mg loses both 3s2 electrons to form Mg+2
Al loses three electrons from 3s23p1 to form Al+3
http://jchemed.chem.wisc.edu/JCESoft/CCA/pirelli/pages/cca2ferrofluid.html
Chemistry SOL Review—Atomic Structure
Anions, Cations, and Electron Configuration
Anions form by gaining valance electrons to take on a noble gas configuration
(ns2np6)
So F becomes F1- by gaining a 2p electron to have the new valance
configuration 2s22p6.
S becomes S2- by gaining two 2p electrons to have the new valance
configuration 3s23p6.
N becomes N3- by gaining three 2p electrons to have the new valance
configuration 2s22p6.
Chemistry SOL Review—Atomic Structure
Isotopes: elements with the same number of protons, but a different
number of neutrons.
12
C
6
13
C
6
Carbon-14 has ___ protons and ___ neutrons
14
C
6
Chemistry SOL Review—Atomic Structure
Isotopes: elements with the same number of protons, but a different
number of neutrons.
12
C
6
13
C
6
Carbon-14 has 6 protons and 8 neutrons
14
C
6
Chemistry SOL Review—Atomic Structure
Isotopes: elements with the
same mass, the same number
of protons, but a different
number of neutrons.
12
C
6
13
C
6
14
C
6
You figure out the average atomic mass of a compound by using
a weighted average of the mass number for each isotope.
Example: a sample contains 10% C-13, 60% C-12 and 40% C-14.
The average atomic mass is
(0.10 x 13) + (0.60 x 12) + (0.30 x 14) = 12.7
Radioactivity

Radioactivity: Spontaneous changes in a
nucleus accompanied by the emission of
energy from the nucleus as a radiation.

Radioactive Half-Life: A period of time in
which half the nuclei of a species of
radioactive substance would decay.
Alpha radiation
Alpha radiation is the least penetrating. It can be
stopped - or absorbed - by just a sheet of paper.
 Beta radiation
Beta radiation can penetrate air and paper. It can be
stopped by a thin sheet of aluminum.
 Gamma radiation
Gamma radiation is the most penetrating. Even small
levels can penetrate air, paper or thin metal. Higher
levels can only be stopped by many centimeters of lead
or many meters of concrete.

Chemistry SOL Review—Atomic Structure
Development of the Atomic
Model
Thompson Model
 Rutherford Gold Foil
Experiment and Model
 Bohr Model
 Quantum-Mechanical
Model

The problems of language here are really serious. We wish to speak
in some way about the structure of the atoms. But we cannot speak
about atoms in ordinary language.
Heisenberg
Chemistry SOL Review—Atomic Structure
Thompson Model

The atom is a positively charged diffuse
mass with negatively charged electrons
stuck in it.
From Mark Rosengarten’s New York Regent’s Powerpoint
Chemistry SOL Review—Atomic Structure
Rutherford Model

The atom is made of a small, dense, positively
charged nucleus with electrons at a distance, the vast
majority of the volume of the atom is empty space.
Alpha particles shot
at a thin sheet of gold
foil: most go through
(empty space). Some
deflect or bounce off
(small + charged
nucleus).
From Mark Rosengarten’s New York Regent’s Powerpoint
Chemistry SOL Review—Atomic Structure
Bohr Model

Electrons orbit around the nucleus in energy levels
(shells). Atomic bright-line spectra was the clue.
From Mark Rosengarten’s New York Regent’s Powerpoint
Chemistry SOL Review—Atomic Structure
Quantum-Mechanical Model
Electron energy levels are wave functions.
 Electrons are found in orbitals, regions of space
where an electron is most likely to be found.
 You can’t know both where the electron is and where
it is going at the same time.
 Electrons buzz around the nucleus like gnats buzzing
around your head.

From Mark Rosengarten’s New York Regent’s Powerpoint