The Structure of an Atom

&

The Periodic Table

“The Atom”I. Atom- The building blocks of matter.

A. Atoms have three parts:

1. Protons (Positive Charge)

2. Neutrons (Neutral Charge)

3. Electrons (Negative Charge)

B. Protons and Neutrons are in the center of the atom. This is called the nucleus.

C. Protons and Neutrons determine a substances identity, and an electron determines its reactivity.

Periodic Table of ElementsI. The Periodic Table of Elements is the collection of all known substances in the world.

B. The elements on the periodic table are arranged according to their proton, neutron, and electron make-up.

C. There are 4 characteristics of each element that you need to understand.

1. Atomic # - This defines what the element is or how many protons the element has.

A. Element- a substance that can not be broken down into a simpler substance.

18

8A

* Since elements are electrically neutral, the # of protons equals the # of electrons.2. Atomic Symbol – This is the symbol for the element. Could be English or Latin letters.

* Why English or Latin letters?3. Atomic Mass – Average Mass of the element or the total number of neutrons and

protons in an element.* The mass – the atomic # = the number ofneutrons the element has.

* Atoms of different elements have different atomic numbers.

* Atoms of the same element can have different numbers of neutrons. These are called isotopes.

* Isotopes have the same atomic number, but a different mass number.

4. Electron Configuration – Often Called groups. * Electron Configuration tells you where an elements electrons are. * This determines what an element will react with.

* All atoms of a given element have the same number of protons & electrons.

* Every atom goal is to have its outer energy level (Shell) filled with electrons. If it is filled this element is said to be stable (not likely to react).

* Group 18 (8A) are stable.

AS. # of Electrons E.C.

He 2 1s2

Li 3 1s22s1

Be 4 1s22s2

O 8 1s22s22p4

Cl 17 1s22s22p63s23p5

K 19 1s22s22p63s23p64s

1

Add two electrons to each s sublevel, 6 to each p sublevel, 10 to each d sublevel, and 14 to each f sublevel.

Reading Information on Periodic Table

6

C

Carbon12.011

Electron Configuration

Atomic Number

Symbol

Name

Average Atomic Mass

*Memorize*Atomic # = # of protons# of protons = # of electronsAtomic mass = # of protons + # of neutronsElectron Configuration = # of electrons in outer most energy level (shell).

Why is the mass of carbon a decimal?

16

4A

Practice

3

Li

Lithium6.941

What is the atomic number of Li?How may electrons are in Li?What is the mass number?How many neutrons are in Li?How many electrons are in Li’s outer shell? What will Li react with easily?

Look at the periodic table in your notes:

What is the name of an element that has 47 protons?

1

1A

With your partner: Choose an element from the periodic table. Create a practice set of questions similar to

the questions on slide 8 of your notes. Have your partner complete the questions. Turn in both question sets when finished.

PARTS OF THE PERIODIC TABLE

Period – horizontal row Group – vertical columns; they are numbered 1 –

18 Family – specific name describing one or more

groups; ex: Column 18 is the noble gases Elements in the same group have the same

number of valence electrons (electrons in their outer shell)

CLASSES OF ELEMENTS

Metals – left and center part of periodic table Conduct heat and electricity

Have Luster

Malleable

Ductile

All are solid at room temperature(except mercury)

CLASSES OF ELEMENTS Cont.

Nonmetals – right side of the periodic table Very abundant in nature Poor conductors of electricity and heat, brittle, many are

gases Hydrogen is the only exception

CLASSES OF ELEMENTS Cont.

Metalloids – some properties of metals and some properties of nonmetals

They are found along the border between metals and nonmetals

They are semiconductors

CLASSES OF ELEMENTS Groups Activity:

You will be assigned one of the following groups: Alkali Metals, Alkaline Earth Metals, Transition

Metals, Boron Family, Carbon Family, Nitrogen Family, Chalcogens Family, The Halogens, & The Noble Gases

Create a poster that has at least 10 facts about the family or group assigned

5 of the facts could be related to #1 on your study guide. The winners will be hung outside in the hall