Periodic Trends Notes

Periodic Trends Notes The periodic table organizes all known elements according to their number of protons. The unique shape of the table reveals the ways in which the electrons are organized around the atom in energy levels.

Periodic Trends Notes The structure of an element (especially the number of protons and the number of electrons) will determine the physical and chemical properties of the element (how it will appear, how it will act, etc.) The periodic table can be broken into regions where all the elements in a region have very similar properties. These regions (and sub-regions) are commonly given names.

Periodic Trends Notes The largest region is the Metals. They all have certain characteristics in common. They conduct heat and electricity very easily, they are lustrous (shiny), malleable (can be bent, flattened, etc.), and ductile (can be drawn into wires).

Periodic Trends Notes The second largest region is the Non-metals. Are generally gases amd poor conductors of heat and electricity, and when solid are dull and brittle (can be broken or shattered).

Periodic Trends Notes Another region is the Metalloids. These elements (green on page 178-179) have characteristics of metals and non-metals, which vary with the element. (Left: selenium, Right: silicon)

Periodic Trends Notes Noble gases are located on the far right and rarely (some never) react with other elements in chemical reactions. This is because they have enough electrons to fill up the p orbital for a total of eight, which makes them very stable. Table Team Review —what Noble gas is represented on the right?

Periodic Trends Notes Octet Rule: This rule states that atoms will be more stable if they have a filled s and p orbitals for their outermost electrons (called valence electrons). Many elements will either lose or gain electrons from other atoms in order to achieve this full “octet” (outermost 8 electrons).

Periodic Trends Notes Rows on the periodic table (horizontal) are called periods. The number of the period will correspond with the energy level (n) of the outermost electron(s).

Periodic Trends Notes The periodic table can also be broken up into sub-regions called groups. Each column (up/down) is a group, so the far left column is known as group 1, and the far right column (noble gases) is called group 18.

Periodic Trends Notes Typically groups that are next to each other will have similar chemical properties, and the further away two groups are the more different they will be.

Periodic Trends Notes Some groups have names: Group 1 is called the Alkali Metals. They are soft and highly reactive. This is because they have a single electron in their s orbital, which can be lost very easily in chemical reactions, which will make them more stable. Above: Cutting Na (Sodium with a pocket knife)

Periodic Trends Notes Group 2 is called the Alkaline-Earth Metals. They are less reactive than Alkali Metals because they have two electrons in the s orbital, which are more difficult to lose in order to become more stable. They are also harder and more dense (therefore stronger) and Alkali Metals. However, they are still very reactive.

Periodic Trends Notes (Right: Lanthanum) Groups 3-12 are called Transition Metals. They widely vary in chemical properties. Among the transition metals are the two rows on the very bottom (f sub-energy level). The first row is called the Lanthanides, and the second row is called the Actinides. (Right: Lanthanum)

Periodic Trends Notes Group 17 is called the Halogens. These are the most reactive non-metals, because they need only one electron to fill their octet and become more stable.

Periodic Trends Notes Hydrogen is the only element that composes its own region of the periodic table (Period 1; Group 1).

Table Team Review What group or region of the Periodic Table are the following elements found in? Strontium (Sr, #38) Tantalum (Ta, #73) Curium (Cm, #96) Antimony (Sb, #51) Sulfur (S, #16)

Table Team Review What group(s) or region of the Periodic Table are the following elements found in? 1. Alkaline Earth Metal, 2. Transition Metal, 3. Actinides (Transition Metal) 4. Metalloid, 5. Non-Metal

What will they do with their electrons in a chemical reaction? Region/Group Review What will they do with their electrons in a chemical reaction? Strontium (Sr, #38) Tantalum (Ta, #73) Curium (Cm, #96) Antimony (Sb, #51) Sulfur (S, #16)

What will they do with their electrons in a chemical reaction? Region/Group Review What will they do with their electrons in a chemical reaction? Strontium (Sr, #38)—loses two electrons Tantalum (Ta, #73)—unpredictable Curium (Cm, #96)—unpredictable Antimony (Sb, #51)—gain 3 electrons Sulfur (S, #16)—gain 2 electrons

Region/Group Review What physical appearance do they have? Strontium (Sr, #38) Tantalum (Ta, #73) Curium (Cm, #96) Antimony (Sb, #51) Sulfur (S, #16)

Region/Group Review Strontium (Sr, #38)

Region/Group Review Tantalum (Ta, #73)

Region/Group Review Curium (Cm, #96)

Region/Group Review Antimony (Sb, #51)

Region/Group Review Sulfur (S, #16)