1. Elements & The Periodic Table
Chapter 3
Elements & The Periodic Table

2. Section 1 Introduction to Atoms
Matter
Anything that has mass and takes up space.
Atom-basic part of matter
Atom means indivisible (can’t be divided) in Greek.
Atomic Theory-atoms are the building blocks of matter.

3. Structure of the Atom Made up of 3 small parts. 1. Protons 2. Neutrons
3. Electrons

4. Protons
Found in the nucleus
Have a positive charge (+)

5. Neutrons
Also found in the nucleus
No charge- neutral

6. Electrons Found on energy levels outside the nucleus.
Has a negative charge (-)
Electrons are the smallest part of an atom.
Found on energy levels
Also known as energy rings/electron cloud

7. Energy Levels of Electrons
Surround the nucleus.
The number of electrons on each energy level are: 2,8,18,32,32,18,8,2
Must fill up energy ring before going to the next ring.
Last ring are valance electrons.

8. Mass of an Atom (Atomic Mass)
Equal to the number of particles in the nucleus.
Protons + Neutrons = Mass

9. Atomic Number The number of protons AND the number of electrons.
Protons and electrons are always the same number.

10. Atoms and Elements
There must be an equal amount of positive and negative charges.
Because of this……
ATOMS ARE ALWAYS NEUTRAL, THEY HAVE NO CHARGE.

11. Mass Number and Isotopes
Isotopes-atom of the same element with a different number of neutrons.
Isotopes that are in nature are unstable.
They are radioactive
The number of neutrons does not affect the charge, only the mass.
The mass number helps tell one isotope from another.

12. Example of Isotopes

13. Section 2-Organizing the Elements
Periodic-to have a regular repeating pattern.
Dmitri Mendeleev- created the first periodic table
Ordered the table from lowest to highest mass (Big Problem)-they all didn’t fit in the right spots.

14. Henry Moseley- arranged the elements in order of increasing atomic number.
He designed the modern periodic table.
He discovered this pattern had no irregularities.

15. Columns and Rows
Columns (groups)-represent elements with similar properties and electron arrangements.
Rows (periods)-represent increasing atomic number, go from metals to nonmetals.

16. Section 3-Metals Properties of Metals:
Luster: Surface will reflect light (shiny)
Conduct heat and electricity
Useful to make cooking utensils and wire
High melting point (except pure gold and pure silver) because they are soft metals.
Pure gold and pure silver are not used alone in jewelry and coins, they are combined.
Gallium melts at room temperature.
Mercury is a liquid at room temperature.

17. Malleability Most useful property of a metal.
Can be flattened, bent, and shaped without breaking.
Ductile-can be pulled into wire.

18. Alkali Metals: Group 1 Li, Na, K, Rb, Cs, Fr Most reactive
Combine very easily with other elements
All have one electron in the outer shell
Found in nature
ALWAYS found in compounds
Combine to form salts
Soft and easily cut with a knife
Low density
Melt at low temperatures

19. Alkaline Earth Metals: Group 2
Reactive, but not as reactive as group 1
2 valence electrons
Occur in nature and combine with other elements
Magnesium and calcium are the most common
Calcium makes up bones and teeth
Used for building materials such as cement.
Used for medicine-Magnesium hydroxide-milk of magnesia used for upset stomachs

20. Transition Metals Most of the elements fall into this group
Hard and shiny
High melting point
Good conductors of electricity
Less reactive, but can combine with other elements
Fe, Co, Ni are magnetic
Found in ores-minerals containing large amount of metal compounds

21. Rare-Earth Metals Separate rows at the bottom of the periodic table
Lanthanides
Elements except 61 occur in nature
Occur in small amounts in the earth’s crust
Small amounts are used in lasers
Create the red color in TV

22. Other
Actinides-the rest of the periodic table
Man made (Synthetic)

23. Nonmetals Properties No luster Poor conductors Dull and brittle
Many are gases at room temperature
Have many electrons in their outer shell
Located to right of the zigzag line

24. Metalloids Properties Shiny, but not much luster
Conduct heat and electricity, but not as good as metals
Semiconductors-Ex. Silicon will conduct electricity only at certain temperatures.

25. Boron Group Only element in group 13 that is not a metal
Brittle black metalloid
Aluminum is the most abundant metal on Earth.

26. Carbon Group Only nonmetal in group 14 Found in ALL living things
2 forms:
Graphite (pencils)
Diamonds

27. Nitrogen Group Only gas in group15 80% of the air we breathe
Essential to living things and for making proteins

28. Oxygen Group Only gas in group 16 Most abundant element on Earth
Most important element

29. Halogen Group Known as salt formers Elements in group 17
Found in most foods that we eat
Combine with metals to form salts
What metals do they combine with?

30. Noble Gases Group 18 Contains 6 colorless gases
DO NOT combine with any other elements
All exist in the Earth’s atmosphere

31. Hydrogen Properties do not fit with any other group
Reacts easily with other elements
Can act as a metal or a nonmetal