The Periodic Table Trends - Pg Bonds – Pg 334

Periodic Table Is a chart that lists atoms by their atomic number and their electron configurations (arrangement of electrons) Periodic – pattern keeps repeating Each box contains 4 things: –Its name –Its symbol –Its atomic number (# of protons/electrons) –Its atomic mass (At the bottom)

Going from up to down Each row is called a period Each element has another orbital filled to capacity (1 st – 2e -, 2 nd – 8e -, 3 rd – 8e - ) As orbits are filled, the atomic radius (size) also increases Elements are less reactive as we go down the rows

Going from left to right Each column is called a group A proton and electron is added to every element. Ex: H – 1 proton,He – 2 protons Li – 3 protons Be– 4 protons/electrons So the atomic number (protons) increases. The number of valence (outermost) electrons also increases

In each group (column) There are the same number of valence electrons in the group Every element in the group has similar properties because of the same number of valence electrons. Ex: H – 1 valence electron Li – 1 valence electron Na – 1 valence electron

Group 1 – Alkali Metals Properties: –Have an extra valence electron and are very reactive –Very soft or brittle –Not found freely in nature because of their high reactivity Ex: Li, Na... s-orbitals are filled first

Group II – Alkali Earth Metals Properties –Two extra valence electrons that are easily lost, but not as easily as Alkali Metals –Less reactive than the Alkali Metals –Not very soft –S-orbitals are filled

Group VII Halogens Properties –These are non-metals –They easily gain an electron to form a negative ion (Cl - ) –Very reactive, reacts rapidly with Groups I and II –P - orbitals are filled Ex: F, Cl, Br, I

Group VIII – Noble Gases Properties –Non-metals –Completely filled valence electrons –Because of completely filled valence electrons, they are highly NON-reactive. –P-orbitals are filled

Bonds Pg 334

Two types of bonding Covalent Bonds –Electrons are shared by two atoms –Ex: Nitrogen has 7 electrons, it shares with another atom to form N 2

Ionic bonds In this type of bond, electrons from one atom are removed and attached to another atom, resulting in positive or negative ions Generally involves 1 metallic atom and 1 non-metallic atom or 1 atom from the left side and 1 from the right of the table Ex: NaCl

Difference btn covalent & ionic bonds Atoms are from the SAME side of the periodic table 1 atom is from the left and the other is from the right side of the table

Review Periodic table is an arrangement of atoms based on their atomic number Difference between Alkali Metals and Alkali Earth metals Halogen and Noble gas groups Difference between covalent and ionic bonds