Fundamental Particle Definitions

1. Matter – anything that takes up space and has mass

2. Atom – smallest whole particle known to man3. Element – any substance that can not be

broken down into other substances by chemical reactions

4. Compound – two or more elements that have combined in a fixed ratio

5. Trace element – elements in minute quantities

6. Neutrons – a subatomic particle with a neutral charge

7. Protons – a subatomic particle which has a positive charge

8. Electrons – a subatomic particle that has a negative charge

9. Dalton – a unit of measurement for neutrons and protons (1.7 x 10-24)

10. Atomic number – the number of protons in the nucleus

11. Atomic weight – the total atomic mass of an element

12. Isotope – an atom that varies its form by changing the number of neutrons in the element

13. Energy – the ability to do work

14. Potential energy – stored energy due to position or location

15. Electron shells – the different states of potential energy for electrons in an atom

16. Orbital – the 3d space in which an electron is found 90% of the time, probable location.

17. Valence electrons – the outer most shell of electrons

18. Covalent bonds – atoms that combine

by sharing valance electrons

19. Electronegativity – the attraction of an atom for the electrons of a covalent bond

20. Ionic bond – a type of bonding in which one atom strips away an electron from another atom

21. Ion – a charged atom22. Hydrogen bond – occurs when a hydrogen atom

covalently bonded to 1 electronegative atom is also attracted to another electronegative atom

23. Chemical reaction – the making and breaking of chemical bonds

24. Reactants – the starting materials in a chemical reaction

25. Products – the result of a chemical reaction

MatterMatter consists of chemical elements-anything

which occupies space and has mass.Matter is found in two ways; pure-form or

compoundsThe Greeks first proposed four elements that made

matter; earth, air, fire, and water.Scientists later discovered 92 naturally occurring

elementsThey can be man-made or naturally occurringTwo or more elements may combine to form

compoundsThey can be found naturally in three ways called

phases; solid, liquid, and gas

Earth

Air

Fire

Water

Atoms Movie

ElementsThere are 92 known elements (naturally occurring)These elements are found on the periodic table of

the elementsSome different elements combine together to form

compoundsTable salt is a compound made up of sodium and

chlorineIt is written using the abbreviation NaClNa = Sodium and Cl = chlorine

The 92 elements are found on the periodic table of the elements

Symbols for Elements

• Symbols are letters that represent the elements on the periodic table

1. If only a single letter, it is Capitalized.

2. If two letters, the 1st is Capitalized and

the 2nd is lower case.

Example: Ca not CA

Periodic Table of the Elements

• Check out the initials for Aluminum in this example off of the Periodic Table:

Periodic Table of the Elements

• The number of protons in an atom is listed above each abbreviation. It is called the Atomic Number.

Periodic Table of the Elements

• The number listed underneath the abbreviation is the Atomic Weight.

C Hopkins café mighty-good food never closed zundays.

• C-Carbon Ca-Calcium• H-Hydrogen Fe-Iron• O-Oxygen Mg-Magnesium• P-Phosphorus F-Fluorine• K-Potassium Na-Sodium• I-Iodine Cl-Chlorine• N-Nitrogen Zn-Zinc• S-Sulfur

The atom is the smallest unit to have properties of an element

About one million fit onto a period at the end of a sentence They are comprised of neutrons, protons, and electrons Neutrons and protons are neatly packed in the nucleus Neutrons and Protons have almost exactly the same mass

Each one has the mass of ~1.7 x 10-24 gramsElectrons are 1/2000 the size of + and N

The number of protons unique to an element is the atomic number

The atomic mass is the total of protons and neutrons in the nucleus

Proton = 1.007 Daltons Neutron = 1.009 Daltons

Atomic Particles

Structure of an Atom

ProtonElectron (electron cloud)

Neutron

Mass Number =

Protons + Neutrons

Atomic Number =

Number of protons

Isotopes

• When the number of protons in an atom changes it becomes a different element

• Atom is electrically neutral when there are more neutrons than protons

• Atoms of the same element that have a different number of neutrons are called isotopes

• Ex. C12 = 6p +6n C14 = 6p + 8n

Ions

• Electrically charged atoms are called Ions• The number of protons is not equal to the

number of electrons• Ions are attracted to each other when they have

opposite charges

• Ex. Na+ + Cl- = NaCl = salt• Ex. Na+ + F- = Sodium Fluoride for

toothpaste

Combinations of Atoms

• Atoms combine by sharing their outermost electrons in their electron clouds

• When two atoms are combined a molecule is formed

Bonds

• Ionic Bond – Positive and Negative ions combine and electrons are transferred– Ex. NaCl

• Covalent Bond – Electrons are shared– Ex. H2O

Name that term…..

1. What is the smallest particle to possess the qualities of an element?

2. Where are + and n found in an atom?

3. How do you know how many electrons are in an atom?

4. What does the atomic number represent?

5. What does the atomic mass represent?