1. Atoms And The Periodic Table

2. Atomic Structure

3. Element – matter that is composed of one type of atom
Elements are abbreviated in scientific shorthand – either a letter or a pair of letters called chemical symbol. Ex: Aluminum – Al Copper – Cu
Atom – smallest piece of matter that still has the properties of the element.

4. Protons – positive charge (1+) Neutrons – neutral or no charge Electrons – negative charge (1-) Nucleus – located in center of atom consists of protons and neutrons; electrons surround the nucleus

5. Electrons in Energy Levels
Electron Cloud – (current) model which shows electrons travelling in specific energy levels around a nucleus; electrons closest to nucleus have low energy, electrons farther away have high energy.
Electrons in Energy Levels
Shell
Number of electrons 1 2 8 3 18 4 32
* Last energy level can only hold max of 8 electrons – H and He are exceptions

6. Masses of Atoms

7. Smaller particles of matter called quarks exist but scientist still consider atoms the basic building blocks of matter
Quark – smaller particles that make up protons and neutrons – six quarks are to exist
Atomic mass – composed mostly of protons and neutrons in the nucleus – also called mass number

8. Atomic number
the number of protons in an atom; number of protons also identifies the element
* If you needed to find # of neutrons of an atom:
# of Neutrons = mass number – atomic number

9. Isotopes
atoms of the same element that have different number of neutrons.
B­­10­ (Boron – 10) or B11 (Boron – 11)   
Different isotopes have different properties.
Average atomic mass
weighted average mass of an elements isotopes.

10. Common Mass Numbers B 5 6 11 10.81 amu C 12 12.01 amu O 8 16 16 amu Na
Element
Symbol
Atomic
No.
Protons
Neutrons
Mass
Ave. Atomic
BORON B 5 6 11
10.81 amu
CARBON C 12
12.01 amu
OXYGEN O 8 16
16 amu
SODIUM Na 23
22.99 amu
COPPER Cu 29 34 63
63.55 amu

11. The Periodic Table

12. Periodic table – table where elements are organized by increasing atomic number (number of protons) In the late 1800’s, Dmitri Mendeleev devised first periodic table based on atomic mass – however, some elements were out of order. In 1913, Henry G. J. Moseley arranged elements by atomic number and is what we use today.

13. The periodic table is arranged by groups and periods
Groups – vertical columns of elements with similar properties - groups are numbered 1-18.
elements in the same group have the same number of electrons in their outer energy level

14. Periods
horizontal rows of elements that contain increasing numbers of protons and electrons. Period are numbered 1-7
each row in the periodic table ends when an outer energy level is filled

15. Each of the seven energy levels can hold a maximum number of electrons.
Level 1 – 2 electrons Level 2 – 8 electrons 
* outer level can hold a max of 8 electrons – except Hydrogen & Helium (only max 2) 
Electron Dot Diagram
use the element symbol and dots to represent outer energy level electrons. He O Ne Al

16. Metals, Nonmetals & Metalloids

17. Metals
good conductor of heat and electricity, all but mercury are solid at room temperature
* Metals are located to the left of stair step
Alkali Metals
(Group 1) are the most reactive of all metals; don’t occur in nature in their element form
Alkaline Earth Metals
(Group 2) shiny, ductile and malleable; combine readily with other elements

18. Transition Elements
(Group 3 – 12) most familiar metals because they often occur in nature uncombined
Inner Transition Metals – (listed below table)
Lanthanide Series – elements with atomic # 58 – 71
Actinide Series – elements with atomic # 90 –103
Nonmetals
elements that are usually gases or brittle solids at room temperature; most can form ionic and covalent compounds – located to the right of the stair step.

19. Noble gases – (Group 18) exist as isolated atoms
Noble gases – (Group 18) exist as isolated atoms. They are all stable because outer energy level is filled Metalloids – elements that make up stair step; have me have metallic and non-metallic properties Metalloids are part of the mixed groups – which contain metals, non- metals and metalloids (mixed groups are Group 13, 14, 15, 16, 17)