Arrangement of the Periodic Table Notes

ELEMENTS Are made up of all the same atoms Identified by it’s atomic # (# of protons) Arrangement of valence electrons determines the elements properties such as conductivity and reactivity. The 1 st letter in chemical symbol is always capitalized. If there is a 2 nd letter, it is always lowercase. 13 Al Aluminum Read Only

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Groups/Families VERTICAL columns on the periodic table Elements in the same group have the same number of valence electrons –This property makes them chemically similar aka “related” because they have the same reactivity (ability to bond with other elements)

Group 1 (1A) = 1 valence electron Go to the periodic table in your notebook. Draw in the valence electrons for each element as shown. Group 13 (3A) = 3 valence electrons Group 2 (2A) = 2 valence electrons Group 14 (4A) = 4 valence electrons Group 15 (5A) = 5 valence electrons Group 16 (6A) = 6 valence electrons Group 17 (7A) = 7 valence electrons Group 18 (8A) = 8 valence electrons

Valence Electrons The electrons in the outermost energy level Determine how an element will react or combine with other substances –Elements with a full or complete energy level is said to be stable or nonreactive. (2-8-8 Rule)

Periods HORIZONTAL rows on the periodic table Elements in the same period have the same number of energy levels (rings) Period 1 = 1 energy level Period 2 = 2 energy levels Period 3 = 3 energy levels These energy rings should already be drawn on your periodic table from last week’s notes. If they aren’t, draw them in now.

Groups vs. Periods Go up and down like a family tree Related/similar chemical properties Tells us the number of valence electrons Left to right (rows) Tells us the number of energy rings/levels Read Only

Quiz Yourself… How many Groups? How many Periods? Read Only

Major Groups of the Periodic Table Write and underline this title. The next slides will be notes about each of the major groups shown in the picture below.

Family: Alkali Metals- Group: #1 All metals 1 Valence Electron VERY reactive –Can explode if they are exposed to water Never found in nature in their pure form because their 1 valence electron enables easy bonding with other elements Density is extremely low so that they are soft enough to be cut with a knife. Watch the explosive nature of the Alkali metals: kgyApYrY

All metals 2 Valence Electrons Very reactive but less than group #1. –It is easier for an element to “accept” via bonding 1 electron vs. “accepting” 2 causing alkaline- earth metals to be less reactive Denser than alkali metals. Family: Alkaline-Earth Metals- Group: #2

All metals 1-2 valence electrons Less reactive than group #2 Since they are metals, they are ductile, malleable, and conduct electricity and heat Have higher densities and melting points than groups 1 & 2. Lanthanide and Actinide series are considered “Rare Earth Metals” and belong to the Transition Metals Family (part of the Transition Metals) Family: Transition Metals- Group: #3-12

Family: Boron, Carbon, Nitrogen, Oxygen Groups #: Named after the first element in the group Elements change from metals to nonmetals and include the metalloids (on the zig-zag line). Atoms have 10 fewer valence electrons than the group #. –Boron Group #13 (3A) - 3 valence electrons –Carbon Group #14 (4A) - 4 valence electrons –Nitrogen Group #15 (5A) - 5 valence electrons –Oxygen Group #16 (6A) - 6 valence electrons

All nonmetals 7 valence electrons VERY reactive –Only need to gain 1 more electron to be considered full/stable. Fluorine is the most reactive element on the Periodic Table. Family: Halogens- Group: #17

All nonmetals Have a full outer energy level –8 valence electrons - except helium only has 2. –Only elements on the whole periodic table that are unreactive (stable) Sometimes called “Inert Gases” Family: Noble Gases- Group: #18

Hydrogen stands alone 1 valence electron –It is placed on the P.T. in Group 1 because it has the same number of valence electrons but it is a gas rather than a metal Very reactive element because of its 1 valence electron can bond with numerous other elements.

Reactivity Across the Periodic Table The easier an element can have 8 valence electrons, (lose or gain) the more reactive it is. –Group 1 (Alkaline Metals) are the most reactive metals because they only have 1 electron to “lose” to become stable –Group 17 (Halogens) are the most reactive nonmetals because they have only 1 electron to “gain” to become stable

Label the family names on your Periodic Table. Draw a box around Hydrogen since it stands alone.

Assignment Use your Periodic Table to answer the following Element Riddles.