Unit 3 Study Guide Chemistry 5ui2q

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Unit 3 Periodicity, Nomenclature, and organic chemistry 3.1 Mendeleev and the Periodic Table Johann Dobereiner- Classified elements into groups of three (triads). They had similar chemical and physical properties. John Newlands-organized elements in increasing atomic mass and noticed similar properties every 8 elements (octaves) Dmitri Mendeleev- arranged elements in order of increasing atomic mass. He arranged the elements into groups with similar properties, and was challenged because there were missing elements that hadn’t been discovered yet but he knew they existed and left spaces for them on the table. Periodicity Rules: Groups: - In the main element groups, elements in the same group share the same number of valence electrons - Elements in same groups share similar chemical and physical properties Periods: - Increasing atomic mass as you move across a period - Paulo Electron Affinity -increases across period -decreases down group Ionization Energy -increases across period -decreases down group Electro negativity -increases across period

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-decreases down group Atomic Radius - decreases across period - increases down group Shielding Effect - remains constant across period - increases down group Metalloids- The elements around the staircase in the period table -Boron -Silicon -Germanium -Arsenic -Antimony -Tellurium -Astatine Nonmetals- The elements to the right of the metalloids (plus hydrogen) Metals-all the rest ELEMENT PHASES AT ROOM TEMPERATURE!?!?>!>!>!>>!> Names of Groups Group 1-Alkali Metals (excluding hydrogen) Group 2-Alkaline Earth Metals Group 3-12- Transition Metals Group 13-15 Poor metals Group 16-The Oxygen Group Group 17- Halogens (salt formers) Group 18- Noble (inert) gases

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3.2 Periodic Trends The two periods at the bottom of the periodic table are the Lanthanides (rare earth elements) and the Actinides (inner transition elements) Outer electron configuration- based on the element group, you can determine the number of outer electrons and determine the configuration by the block which it’s in. Two factors influence atomic radius and electro negativity are 1. Size of atoms since the bigger atoms can more easily give the outer electron 2. Number of electrons since the number the number in the outer shell determines how

well an atom attracts or gives up electrons. Generally, Metals give up electrons and non metals take electrons based on the electro negativity but there are many exceptions Ionization energy- energy needed to remove an electron forming a cation (positive). (when an atom loses an electron it gets a +1 charge) 1st, 2nd and 3rd ionization energy just refers to how many of the electrons you are removing from the atom. Trend between atomic radius and ionization energy: So, if the atomic radius is small, the electron "feels" stronger pull from the positive nucleus, thus that electron is harder to pull off. Predicting ionic (nuclear) charge: -Group 1: 1+ -Group 2: 2+ -Group 13: 3+ -Group 14: 4+ (but in some cases -) -Group 15: 3-Group 16: 2-Group 17: 13.3 Ionic Bonding and Nomenclature Ionic Compound Composition- They are composed of anions and cations. Charges must balance out to 0.

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Salt- is any metal combining with a non-metal. E.g. KF2 (potassium fluoride). Halide salt- metal combined with a halogen Polyatomic vs. Monatomic -A monatomic ion has only one atom examples are chloride, Cl-, fluoride, F-, sodium Na+ -A polyatomic ion has more than one, e.g sulfate SO42-, nitrate, NO3-, mercurous, Hg22+ Latin and stock nomenclature?!?!!!?

3.4 Covalent Bonding and Nomenclature Diatomic elements- double of the same element in a compound Ex. H2, N2, O2, F2, Cl2, I2, Br2 Sometimes in covalent bonding, the octet rule will not be followed and there will be a stable electron configuration with less than 8 electrons. 3.5 Miscellaneous Bonding Concepts Empirical Formula- The most simplified whole number ratio of the elements in a compound VS. Molecular Formula- the original number of elements in a compound

Binary compound- a compound consisting of 2 different elements

Covalent Bonding- Bonding between 2 non metals and the bonding is equally shared. VS. Ionic Compound- is a bond between metal and non metal

Difference in electro negativity (non polar-balance distribution of electrical charge) 0-0.3=non polar covalent bond

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0.3-1.7= polar covalent bond 1.7-4.0=ionic bond

Metallic Bonding-