Interim 1 Review KEY October, 2014

Periodic Table How is the periodic table organized? In order of atomic number, grouped in columns by valence electrons and in rows by energy levels for those electrons. The atomic number is the same number as ____the number of protons__ and ___electrons in a neutral atom ________ Why are groups in the Periodic Table called families? Elements in a family have similar chemical properties, because they have the same number of valence electrons. Name two characteristics of metals and well as two examples. Good electrical conductors, thermal conductors, high luster (shiny), malleable, ductile. Examples: gold, silver, iron, copper, nickel, anything to the left of the zig-zag metalloids Name two characteristics of nonmetals as well as two examples. Poor conductors of electricity and heat Brittle or gaseous, tend to take electrons in reactions. Expl: oxygen, nitrogen, carbon (pencil lead, diamond), chlorine, sulfur Name two characteristics of metalloids as well as two examples. Somewhat like metals and non-metals. Semiconductors Expl: silicon (high luster, bonds like carbon) Boron, antimony, germanium

Standards of Measurement What are you measuring Definition SI Unit (Symbol) Volume How much space a substance fills mL or cm3 Mass How much matter is in a substance (based on amu’s) Gram (g) Weight How much gravity pulls on a mass Newton (N) Time Duration of an event Second (sec) Temperature How fast molecules and atoms move (kinetic energy) Kelvin (K) Density How much mass is in a given volume (mass per volume) g/cm3 or g/mL How do you calculate the volume of regularly shaped object? Using displacement, how do you calculate the volume of an irregularly shaped object. L x W x H The difference in water level before and after an object is put into the water. mL of water = cm3 of solid

Atoms and Molecules What is Matter? Anything that takes up space and has mass What is the law of conservation of matter? Matter is neither created nor destroyed in a chemical reaction What is an atom? Smallest particle into which an element can be broken and still keep its identity (properties) What is a molecule? Smallest particle into which a compound can be broken and still keep its identity (properties) How is an atom different than a molecule? Atom is made of protons, neutrons, electrons … one element. Atoms bond together to make compounds. They do this by sharing or transferring electrons with other atoms. State two examples of a pure substance Pure elements: anything listed on the Periodic Table of Elements Compounds: sugar, baking soda, water, sulfuric acid What is a mixture? A combination of elements and/or compounds which are not chemically bonded to each other. Homogeneous = same throughout (iced tea or KoolAid). Heterogeneous = not evenly mixed (tossed salad, salt & pepper) Why is a mixture not considered a pure substance? Particles are not the same throughout. Can be divided into different components with out changing the identity of those components. Define Element All atoms have the same identity and are not chemically bonded with any other element(s) Define Compound Atoms of different elements sharing or exchanging electrons to form a substance with its own properties Define Mixture Combination of elements, compounds, etc which are not chemically bonded to each other. What makes an element different than a compound and mixture? All the same atoms What makes a compound different than an element and mixture? Atoms are chemically bonded together What makes a mixture different than an element and compound? Substances are mixed without bonding

The Atom and States of Matter Parts of the Atom Proton: Where is it located and what charge does it have? In nucleus of atom; positive charge Electron: Where is it located and what charge does it have? Outside nucleus of atom, in electron cloud or shells; negative charge Neutron: Where is it located and what charge does it have? In nucleus of atom; no charge (neutral) Name the two structures that make the nucleus. Protons and neutrons What part of the atom has the most mass? Nucleus has almost all of the mass of an atom What part of the atom takes up the most space? Electron cloud takes up the most space Solid (energy level and how do the particles move) lowest energy state … Atoms/molecules vibrate in place, not changing shape; definite volume Liquid (energy level and how do the particles move) Midrange energy state … Atoms/molecules move freely, slide past each other, take the shape of container; but has a definite volume Gas (energy level and how do the particles move) High energy state … Atoms/molecules move independently, take the shape and volume of container Plasma(energy level and how do the particles move) High energy state … Atoms/molecules move like a gas, but electrons have broken off, making ions – light is emitted

Properties of Matter Define Give Examples (as many as possible) Physical Property Color, luster, solubility, state of matter, density, mass, malleability, ductility, brittleness, viscosity, melting/freezing point, boiling point Chemical Property pH, reactivity (with acid, water, oxygen, etc), flammability, combustibility How is a physical change different than a chemical change? Physical: does not change the identity of the substance; it is more likely to be reversible. Chemical: new substance is formed with new properties, chemical bonds have changed Explain two physical changes Explain two chemical changes Dissolving sugar into water or tea. Tearing a piece of paper or breaking pencil Melting butter or metal Reshaping metal into jewelry These all have the same substance B4 & after Caramelizing sugar (changes odor &color) Burning wood or paper (gas produced, light and heat released, carbon ashes) Both of these examples involve a substance reacting with oxygen in the air What clues indicate a chemical change has occurred through your observations. Included in answers above

Properties of Matter Vocabulary Property Definition Chemical or Physical Density Amount of mass per unit volume Physical Precipitate Solid forms when mixing 2 liquids Chemical Change of State Changing solid, liquid, gas, plasma with the addition or removal of energy (especially heat) physical Melting Point Temperature at which solid becomes a liquid (usually same temperature as freezing point: liquid  solid) Boiling Point Temperature at which liquid boils to rapidly vaporize Malleability Ability to be shaped or molded Ductility Ability to be drawn/pulled into wires Reactivity Likelihood to chemically react with another substance (expl reactive with oxygen, acids, bases, water, etc) Combustibility Likelihood to explosively react with oxygen Conductor Able to transmit electricity or heat Vaporization Liquid (or solid) changing to vapor (gas)

Periodic Table Vocabulary Define the following terms Atomic Mass Unit The mass in one proton or neutron Note: the atomic mass of an element is the weighted average of all naturally occurring isotopes Mass Number The number of protons + neutrons in a specific isotope of an element. Note: this is always a whole number Period Horizontal row in the periodic table – this represents how many energy shells have electrons in them. (expl,: the third row has electrons in levels 1, 2, and 3) Group/Family Vertical column of the periodic table – these elements are grouped together because they have the same number of valence (outer shell) electrons, and therefore have similar chemical properties Valence Electrons Electrons in the outermost electron shells. These electrons are the only ones that might interact with other elements to form chemical bonds. Atoms try to have a complete outer shell (usually 8 electrons)