Periodic Table PS-2.3 Explain the trends of the periodic table based on the elements’ valence electrons and atomic numbers. PS-2.5 Predict the charge (oxidation numbers) that a representative element will acquire according to the arrangement of electrons in its outer shell.

What are the three subatomic particles of the atom? Proton Electron Neutron

What are the charges of each? Protons  Positive Electrons  Negative Neutron  Neutral

What are the charges of each? Protons  Positive Electrons  Negative Neutron  Neutral

What particles form neutrons and protons? Quarks

Where are each located? Proton  inside the nucleus Neutron inside the nucleus Electron  outside the nucleus Electron Cloud

What is the net charge of the nucleus? Positive

What determines the identity of the atom? Protons

History of the Periodic Table 1871: Dimitri Mendeleev Organized elements together that had similar properties. Developed the Periodic table.

The Periodic Table

Period Horizontal row on the periodic table Period # = the number of energy levels an element occupies

# of energy levels From left to right: atoms in the same period contain the same number of energy levels Energy levels increase as you move down the periodic table

Group/Family Vertical column on the periodic table Similar Chemistry Ex: Cu, Ag, Au – shiny metals, good conductors

Group/Family Names Group/Family Name Valence Electrons 1 Alkali Metals 2 Alkaline Earth Metals 13 3 14 4 15 5 16 Oxygen Family 6 17 Halogens 7 18 Noble Gases 8 (except He)

Categories Metals Nonmetals Metalloids Shiny exist as solids at room temp good conductors Nonmetals Gasses or brittle solids Not conductors Metalloids Elements that contain properties of metals and nonmetals

Group (family) Group # = element’s valence electrons Valence electrons electrons in the outer most energy level determines chemical properties of the element. Each row ends with the outer energy level filled.

Number of Valence Electrons Valence electrons increase by one from left to right across the periodic table From top to bottom in a group: atoms in the same group contain the same number of valence electrons

Group (family) Each group has the same Lewis Dot structure Shows the number of valence electrons for each element

Reading the Periodic Table Chemical Symbol Name Atomic #: tells the # of protons Atomic Mass: Average of all isotopes of an atom Mass #: Protons + Neutrons

Chemically Stable Atoms Noble gases are the only chemically stable atoms They have a full outer energy level Ex. Neon 8 valence e- Helium 2 valence e-

Chemical Stability Atoms that do not have a full outer energy level tend to gain, lose, or share valence electrons in order to become stable. Chemical reactions electrons being gained, shared, or lost the number of protons, and neutrons stay the same.

Becoming stable Group 1 tends to lose 1 electron. Group 2 tends to lose 2 electrons. Group 16 tends to gain 2 electrons. Group 17 tends to gain 1 electron. Group 13-15 are less likely than the above to gain or lose electrons. Groups 13-15 tend to lose electrons.

If a neutral atom… A charged particle is called an Ion. Oxidation State: number of a electrons an atom will gain/lose to become stable Loses electrons: forms a positive ion. (metals) Gains electrons: forms a negative ion (nonmetals)

Diatomic Molecules 7 elements that are so reactive they covalently bond to themselves to form a molecule Only when free in nature