atomic structure

Chemistry SOL Reviewby Anne Mooring (Jamestown High School, Williamsburg VA, 2006)

Part 2: Atomic Structure and Periodic Relationships

1. Parts of the Periodic Table

2. Introduction to the SOL Periodic Table

3. Atomic Structure and the Periodic Table

4. Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.

5. Isotopes and Average Atomic Mass

6. Historical and Quantum Models of the Atom

A calculator will be helpful, but not necessary for this powerpoint.

This section represents 8/50 of the SOL questions

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

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

Chemistry SOL Review—Atomic Structure

An s orbital holds 2 electrons w/ opposite spins

Chemistry SOL Review—Atomic Structure

Each p orbital holds 2e- with opposite spins

Chemistry SOL Review—Atomic Structure

Each d orbital holds 2e- with opposite spins

Chemistry SOL Review—Atomic Structure

The s suborbital fills

The orbitals and the periodic table

Chemistry SOL Review—Atomic Structure

The p suborbitals fill

The orbitals and the periodic table

Chemistry SOL Review—Atomic Structure

The d suborbitals fill

The orbitals and the periodic table

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.

Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.

Chemistry SOL Review—Atomic Structure

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.

Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.

Chemistry SOL Review—Atomic Structure

Atomic Radius: the radius of an atom in picometers

1 2 13 14 15 16 17 18

Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.

Chemistry SOL Review—Atomic Structure

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.

Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.

Chemistry SOL Review—Atomic Structure

First Ionization Energy: The energy needed to remove the first valence electron from a gaseous atom.

Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity.

Chemistry SOL Review—Atomic Structure

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.

Chemistry SOL Review—Atomic Structure

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

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.

126C 13

6C 14

6C

Isotopes: elements with the same number of protons, but a different number of neutrons.

Chemistry SOL Review—Atomic Structure

Carbon-14 has ___ protons and ___ neutrons

126C 13

6C 14

6C

Isotopes: elements with the same number of protons, but a different number of neutrons.

Chemistry SOL Review—Atomic Structure

Carbon-14 has 6 protons and 8 neutrons

126C 13

6C 14

6C

Isotopes: elements with the same number of protons, but a different number of neutrons.

Chemistry SOL Review—Atomic Structure

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

Development of the Atomic Model

• Thompson Model

• Rutherford Gold Foil Experiment and Model

• Bohr Model

• Quantum-Mechanical Model

From Mark Rosengarten’s New York Regent’s Powerpoint

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 shotat a thin sheet of goldfoil: most go through(empty space). Somedeflect or bounce off(small + chargednucleus).

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

Chemistry SOL Review—Atomic Structure

Chemistry SOL Review—Atomic Structure

References

www.markrosengarten.com NY Regent’s Exam Powerpoint