Properties of the Periodic Table The Periodic Table

Properties of the Periodic Table

The Periodic Table Vertical columns are called Groups are numbered from 1 to 18

The Periodic Table Valence Electrons are electrons located on the outermost energy level. Each element in a group has the same number of valence electrons

The Periodic Table Each row is called a period Each period starts with an atom with one electron in the outer energy level and ends with an atom that has a full outer energy level

The Periodic Table has 3 main sections of elements with similar properties: Metals Nonmetals Metalloids

Specifics on Groups of the Periodic Table

Metals Properties of metals include: Conduct heat & electricity Solid at room temperature - all except Mercury (Hg)

Metals Properties of metals include: Reflective, malleable ductile Located on the left side of the Periodic Table

Alkali Metals

Alkali Metals The first column of the periodic table Forms +1 Ions by losing the 1 valence electron The most reactive metals on the periodic table Sodium explodes when exposed to the air http: //video. google. com/videoplay? docid=-2134266654801392897#

Alkaline Earth Metals

Alkaline Earth Metals Second group on the periodic table Also very reactive, but not as much as the alkali metals Forms +2 Ions by losing the 2 valence electrons.

Transition Elements Groups 3 -12 are the more stable Transition Elements They usually exist uncombined with other elements because they are not as reactive

Transition Elements Usually for multiple positive ions. i. e. Copper forms +1 or +2 depending on the compound.

Inner Transition Elements The disconnected rows underneath the rest of the table They fit between groups 3 & 4 in periods 6 & 7

Inner Transition Elements The first row contains the Lanthanides, Lanthanides starting with Lanthanum The second row contains the Actinides, Actinides starting with Actinium They are very unstable because of the high number of neutrons versus protons

Nonmetals

Nonmetals Properties of nonmetals: Usually gases or brittle solids at room temperature Exception is Bromine (liquid) liquid

Nonmetals Properties of nonmetals: Not malleable or ductile Not usually conductive or reflective Form negative ions by gaining valence electrons.

Noble Gases

Noble Gases They are in group 18 of the periodic table They are the most stable of all elements. They don’t react with other elements under normal conditions

Halogens

Halogens Group 17 on the periodic table They are not usually found in nature alone but as salts (Combined with a metal) Some are called diatomic molecules (exist in a molecule of 2 atoms)

Halogens Readily gain 1 valence electron to form a -1 ion. Halogens are very reactive The most reactive non-metals!

Diatomic Molecules Some nonmetals are called exist in a molecule of two atoms joined together This means that Natural Oxygen exists as O 2

Metalloids

Metalloids Elements that have properties of metals and nonmetals Groups 13, 14, 15, 16, and 17 contain metalloids

Metalloids The metalloids are: Boron Silicon Germanium Arsenic Antimony Tellurium Polonium

Metalloids Have a combination of the properties of metals and non-metals In a zig-zag from top of Boron to the bottom of Polonium Anything touching 2 sides of the zig zag is a metalloid (EXCEPT Aluminum)

Periodic Trends

Periodic Trends The periodic table is organized in such a way that repeating patterns, or trends, trends can be seen.

Periodic Trends There are three main trends Atomic mass Atomic radius Reactivity

Atomic Mass Trend As you go from left to right, mass increases As you go from top to bottom, mass increases

Atomic Mass Trend Why? • As we go left to right or top to bottom, there is an increase in amount of matter • Protons and Neutrons increase

Which has more mass? F N Na Sr H or or or O As K Li Xe

Atomic Radius (Size) Trend Atomic Radius is the distance from the center of the nucleus to the outside of the electron cloud Measure in Angstroms (Ǻ)

Atomic Radius (Size) Trend As you go from left to right, radius decreases As you go from top to bottom, radius increases

Atomic Radius (Size) Trend Why? As we go left to right , the nucleus pulls the atom tighter Top to bottom, there are more energy levels being added.

Which has a bigger radius? F N Na Sr H or or or O As K Li Xe

Reactivity Trend Tells how reactive elements are, or how strongly they will interact with other elements As you go from left to right, reactivity of metals decreases, decreases and then the reactivity of nonmetals increases (but stops at the halogens) halogens

Reactivity Trend As you go from top to bottom, reactivity increases on the left and decreases on the right Why? Metals at the bottom lose electrons and nonmetals at the top gain electrons Therefore the corners are the most reactive

Reactivity Trend Most Reactive Metal and Nonmetal Start with “F” Can you guess what they are? Remember the Alkali metal reactivity video… http: //video. google. com/videoplay? docid=-2134266654801392897#

Bohr Models One way to see the trend of Valence Electrons is to draw a Bohr model Remember Bohr placed electrons in specific orbits, orbits or energy levels. 1 st = 2 electrons 3 rd = 18 electrons 2 nd = 8 electrons 4 th = 32 electrons

Bohr Models Lets Draw the Bohr models for some of the elements in group 1 What do you notice?

Lewis Dot Diagrams Soon we will learn that although as many as 32 electrons can sit on an outer energy level, we are only concerned about the outermost 8, which are the valence electrons. This is what we call an Octet (8 Electrons)

Lewis Dot Diagrams We show an element’s octet is filled using a Lewis Dot structure. Let’s draw the Lewis Dot Diagrams for the same atoms and some new ones.

Lewis Dot Diagrams

Valence Electrons become VERY important in our next unit!!!