PS+4+-+3rd+Period+Brown

 Chemical bonding occurs when atoms gain, lose, or share electrons. When this happens, and ion is formed. The way in which chemical bonding occurs defines the type of bond that forms: covalent, ionic, or metallic. Ion: atom or group of atoms carrying an overall positive or negative charge. Covalent: formed by atoms sharing electrons to form molecules. Normally between two non-metaled elements. Ionic: between a metal and a nonmetal Groups 1 and 2, Groups 16 and 17: groups 1 and 2 lose electrons from their outer shells. Groups 16 and 17 gain or pick up electrons to become stable. Electrons: negatively charged particles Nonmetal: have less the number of electrons that they need, so they either gain or share with other nonmetals Stable: when an atom has 8 valence electrons of their outer shell Valence Electrons: electrons on the outer most energy level Chemical Formula: representations of a substance using symbols for its elements Symbol: something used for representing something else, (emblem or sign) Subscript: written below (C and down below it would be a little number 12) Oxidation Number: the charge that results when an atom gains or loses electrons Bohr Model: represents an atom, whichever group the element is in is how many valence electrons and the period is the number of energy levels Criss Cross Method: If you have Na which is 1 plus because it's in group 1 and S which is 2 minus because it's in groups 16. To balance those out, you criss cross and the answer would be Na2S. Charge: if something is positive negative, or neutral Balanced: when an quation is written, on both sides all the elements are equal Nobel Gases: have 8 valence electrons and are in group 18 Metals: lose electrons to achieve a stable noble gas structure Gain Elctrons: nonmetals Lose Electrons: metals Electron Dot Diagram: represents an atom, the symbol in the middle and the number of valence elctrons on the top, right, bottom, and left sides

Paired: if there's 2 dots beside eachother on the top or any side of the symbol in the middle, then those are paired elctrons (the ones on the right side) Unpaired: if there's only one dot on any side then that dot is unpaired (the ones on the tope, bottom, and left sides) PS-4.1... Explain the role of bonding in achieving chemical stability: If it is a metal then it normally loses electrons to another atom so that it can be stable. Reaching chemical stability is the process of losing, gaining, or sharing electrons to have an outer shell of 8 valence electrons. So if it is a nonmetal then it will gain or share electrons with others to become stable. It's all part of each atom bonding together to mantain the stability of an atom. PS-4.2... Explain how the process of covalent bonding provides chemical stability through the sharig of electrons: They share elctrons to become more stable, to reach the 8 valence electrons PS-4.3... Illustrate the fact the ions attract ions of opposite charge from all directions and form crystal lattices: Opposites attract eachother. Positives attract negatives. Which element is stable, exists as a single atom in air, and has a full valence shell? A) Hydrogen B)  helium?* C) gold D) Oxygen What type of element typically loses electrons to form a bond? A) nonmetal B)  noble gas C) metalloid D)  metal * At what ratio will potassium and sulfur form a bionary compound? A) 1:1 B)  1:2 C) 2:1 * D)  3:2
 * QUESTIONS!!!**

Since ionic bonds are formed by sharing electrons, they are considered to be crystalline compounds. Covalent bonds gain, lose, or share electrons and are called molecular compounds. Crystalline compounds (ionic bonds) contain a metal and a non-metal, while molecular compounds (covalent bonds) contain two non-metals. Ionic Bonding Ionic Bond: the electrostatic bond between two ions formed through the transfer of one or more electrons Chemical Formula: a representation of a substance using symbols for its constituent elements Stability: resistance or the degree of resistance to chemical change or disintegration Valence Electrons: an electron of an atom, located in the outermost shell (valence shell) of the atom that can be transferred or shared with another atom Compounds: a pure substance composed of two or more elements whose composition is constant Ion: an electrically charged atom or group of atoms formed by the loss or gain of one or more electrons Charged: amount of electrons in an atom Neutral: a particle without a positive or a negative charge Binary Ionic Compounds are formed when a metal and a non metal are combined. The elements develop an opposite charge, which attracts one to the other. 

Intro to Balancing Equations Balanced: to make an equation equal on both the reactant and product sides Atoms rearrange: to change the atom’s position Counting atoms: to find the number or amount of atoms Subscript: A distinguishing character or symbol written directly beneath or next to and slightly below a letter or number. Coefficient: a number that is constant for a given substance, body, or process under certain specified conditions, serving as a measure of one of its properties Recognizing a balanced equation: when you have the same number of electrons for each element on each side of the equation, the equation becomes balanced Reactants: any substance that undergoes a chemical change in a given reaction Products: a substance obtained from another substance through chemical change. Which of the following processes would result in a chemical change? A.) boiling B.) cutting C.) dissolving D.) digesting* Which of the following involves a chemical change? A.) crushing a cube of sugar to form granules of sugar B.) dissolving sugar granules in water C.) boiling the water and sugar mixture D.) burning a cube of sugar until it turns black and eventually disappears* Rusting is an example of A.) oxidation* B.) combustion C.) physical change D.) precipitation
 * QUESTIONS!!! **

Acids: any substance that produces hydrogen ions in a water solution Hydrogen Ions: ionized hydrogen (h+) found in solutions of all acids Hydronium: hydrated hydrogen ion Strong acid: nearly 100 percent ionized in solution (below 7 on the PH scale) Weak Acid: low percentage of ionized (below 7 on ph scale) Bases: substance that accepts protons Hydroxide: a chemical compound containing the hydroxyl group Strong Base: base with lots of ionized (above 7 on ph scale) Weak Base: base with low ionized (above 7 on ph scale) Conductivity: able to conduct heat, electricity, or sounds PH Scale: decides the acidity or alkalinity in a solution

Indicators: a substance, litmus, which shows a certain extent Neutralization: a reaction between an acid and a base that yields a salt and water.

4.10 Balanced equation: 2H2+O2—2H2O Unbalanced equation: H2+O2—H2O 4.11 To Decrease rate of reaction you can: Decrease temperature Decrease concentration Decrease surface area To increase rate of reaction you can: Add a Catalyst

1) Which chemical equation is balanced?
 * QUESTIONS!!!**

A) 2FeO+4C—Fe+2CO2 **B) SiI4+2Mg—Si+2MgI2**

C) 4Ba+s8—2BaS D) 4HgO—4Hg+3O2

2) Which statement is true about the temperatures of the substances involved in an exothermic reaction?

A) Temperature of product is the same as the reactant C) Temperature of product is lower than the reactants D) temperature of product is same as the reactants
 * B) Temperature of reactant is lower than product

4) What is true in every balanced chemical equation? A) All coefficients have to be multiples of 2 B) The energy change that occurs is exothermic C) Atoms are created when products are formed * D) Mass has to be conserved