Know that elements can be organized by similar properties such as reactive metals, reactive nonmetal, gases, metals and acids. Understand when substances interact to form new substances, the new substances may be very different from the original. Understand the amount of mass does not change.

Periodic chart

Periods In each period (horizontal row), the atomic numbers increase from left to right. The periods are numbered 1 through 7 on the left-hand side of the table. Elements that are in the same period have chemical properties that are not all that similar. Their properties change gradually as you move from left to right on the row.

Consider the first two members of period 3: Sodium (Na) and Magnesium (Mg). In reactions, they both tend to lose electrons. Sodium loses one electron, while Magnesium loses two. (metals) Chlorine (Cl), down near the end of the period, tends to gain an electron (it’s a nonmetal).

Families Elements that are together in a column have similar properties. The columns are called families or sometimes groups. The properties that are similar are usually chemical properties, they react with other matter in the same way.

Families The families are labeled at the top of the columns in one of two ways: The older method uses Roman numerals and letters. Many chemists prefer and still use this method. The newer method uses the numbers 1 through 18.

Columns of elements help define element groups Columns of elements help define element groups. Groups are elements that have the same outer electron arrangement. The outer electrons are called valence electrons. Because they have the same number of valence electrons, elements in a group share similar chemical properties. The Roman numerals listed above each group are the usual number of valence electrons. For example, a group VA element will have 5 valence electrons.

Atom Drawing Everyone will draw an atom. Group two pick an atom to draw in the 5th or 6th period Group one pick an atom to draw in the 3rd or 4th period Give the following info: Name, Symbol, Atomic Number, Atomic mass, Number of electron shells, Number of neutrons.

Draw the following: Nucleus with number of Protons & Neutrons (use plus sign for protons and triangles for neutrons), Electron shells with correct number of electrons on each one (use minus signs in a circle for electrons).

Names of Elements The first letter of any symbol is always capital and the second is always lower case. Some element names use only the first letter of the name for the symbol. Examples: Oxygen – O, Hydrogen – H, Boron – B, Uranium – U etc... Some symbols are used from the first and second letters of the symbol name. Examples: Helium – He, Lithium – Li, Neon – Ne, Silicon – Si, Calcium – Ca etc…

Some symbols are taken from the first letter and another letter found in the name. Examples: Magnesium – Mg, Chlorine – Cl, Plutonium – Pu, Zinc – Zn etc…

Some don’t use any letters from the modern name Some don’t use any letters from the modern name. Symbols not found in the name are symbols used from Latin or Greek terms: Sodium – Na Gold – Au Potassium – K Mercury – Hg Iron – Fe Lead – Pb Silver – Ag Antimony – Sb Tin – Sn Copper – Cu Tungsten - W

Alkali Metals Group 1 of the periodic table. Alkali metals are the most reactive. They easily give away an electron. There is only one electron to give away in the outer shell. They are found in nature only combined with other elements. Properties: soft, easily cut, react with water to form hydrogen gas.

Alkaline-Earth Metals Group 2 Less reactive than Alkali metals. They have two electrons in the outer shell. Less reactive because of the two electrons. Properties: color of silver, higher density than Alkali metals.

Transition Metals Group 3 through group 12 They do not have individual names for each column, they are all called transition metals. They are the biggest group. They do not give up their electrons easily. They are less reactive than the first two groups. Properties: shiny, good conductors of thermal energy & electrical currents

More Transition Metals Lanthanides – Top row at the bottom. Shiny, reactive metals. Used to make steel. Actinides – Second row. All are radioactive. The atoms of actinides can change into atoms of other lighter elements.

Boron Group Group 13 Most abundant element in the Earth’s crust is Aluminum. It is in the Boron group. Boron group elements are reactive but they form oxides that coat them.

Carbon Group Group 14 Nonmetal Can be found uncombined in nature Forms a wide variety of compounds, including many that are necessary for living things. (proteins, fats, carbohydrates)

Nitrogen Group Group 15 The nitrogen family consists of nitrogen, phosphorus, arsenic, antimony and bismuth.   Nitrogen family elements consists of atoms having 5 electrons in their outer energy level. Nitrogen and phosphorus are nonmetals. Arsenic and antimony are metalloids. Bismuth is a metal.

Oxygen Group The Oxygen Family (chalcogens) Group 16 Considered part of the Main Group elements. Consists of the elements oxygen, sulfur, selenium, tellurium and polonium. They can be found in nature in both free and combined states, 3 nonmetals, 1 metalloid & 1 metal. Oxygen is only gas. 6 electrons in the outer level

Halogens Group 17 Five non-metallic elements. The term "halogen" means "salt-former" and compounds containing halogens are called "salts". All halogens have 7 electrons in their outer shells. The halogens exist (room temperature) in all three states of matter. Very reactive non-metals.

Noble Gases Group 18 The six noble gases are found in group 18 of the periodic table. Their oxidation number of 0 prevents the noble gases from forming compounds readily (unreactive). All noble gases have the maximum number of electrons possible in their outer shell (2 for Helium, 8 for all others), making them stable. Under normal conditions they don’t react with other elements

Hydrogen Hydrogen does not match any group. Reactive Colorless, odorless gas Hydrogen is above group 1 because it also has one electron in the outer shell.

Questions Pages 354 – 355 1 -10 answers only 12, 18, 19, 20 short answer – write only the answer. I will put these on my website for tonight

Octet Rule The Octet rule states that atoms lose, gain, or share electrons in order to have a full valence shell of eight electrons. Hydrogen is excluded because it can hold a maximum of two electrons in its valence shell.

Atomic number = # of Protons and is also the number of Electrons Neutrons = Atomic Mass – Atomic Number