Download Topic 4: Classifying Elements What did the early chemists use to

Topic 4: Classifying Elements What did the early chemists use to represent elements? They used pictures and the planets. What do we use today to represent elements? Uppercase and lowercase letters. What are the three major categories that the modern periodic table can be organized into? Metals, non-­‐metals, and metalloids. List FOUR properties of METALS (page 118) solids (except for mercury), shiny, good conductors, malleable/ductile List FOUR properties of NON – METALS (page 118) can be solid, liquid, or gas, not shiny, poor conductors, brittle/non-­‐ductile What are METALLOIDS? (page 118) elements with properties that lie “in-­‐between” metals and non-­‐metals. List the FOUR major CHEMICAL FAMILIES you learned about and state whether they are reactive or stable. Include the group number of each family, and be able to identify them on the periodic table. (page 121 and 124) Alkali Metals, group 1, very reactive Alkaline Earth Metals, group 2, fairly reactive Halogens, group 17, very reactive Noble Gases, group 18, stable/inert Topic 5: The Periodic Table Mendeleev organized the elements into the first periodic table according to what? atomic mass Today, we organize the periodic table according to what? atomic number What is the ATOMIC NUMBER of an element? What is it equal to? It is the number of protons an element has in its nucleus. What is the MASS NUMBER of an element? It is the total of neutrons and protons in an atom. It is also the atomic mass rounded to the nearest whole number. What is the ATOMIC/ELEMENT SYMBOL of an element? The letter(s) used to represent that element. What is the ATOMIC MASS of an element? The average mass of an atom of an element. What is the average mass of an element measured in? (it is three letters) Atomic mass is measured in “amu’s” – atomic mass units. What is a HORIZONTAL ROW in a periodic table called? How many of these are there in the periodic table? They are called periods, and there are 7 of them. What is the VERTICAL COLUMN in a periodic table called (it can have two names)? How many of these are there in the periodic table? They are called groups or families, and there are 18 of them. Topic 6: Chemical Compounds What is a SUBSCRIPT? What does it indicate? Provide an example. The small number on the bottom of a formula. Indicates the number of atoms of that element used. A subscript can also be used to indicate the state that the element/compound is found in at room temperature. EXAMPLE: H2O(l), NaCl(s) What is a SUPERSCRIPT? What does it indicate? Provide an example. The small number at the top of the element. It indicates the charge of the ion. EXAMPLE: O2-­‐ What is a MOLECULE? Provide an example. A group of neutral atoms bonded together. EXAMPLE: H2O à this is one molecule of water What is a DIATOMIC MOLECULE? Provide an example from your notes. A diatomic molecule is always made up of pairs of the same kind of atom. EXAMPLES: O2(g), H2(g) à there are others but know these Name the following examples of MOLECULAR COMPOUNDS (see your notes or textbook to help you): • CO2(g) à carbon dioxide • NH3(g) à nitrogen trihydride or ammonia • CH4(g) à carbon tetrahydride or methane • H2O2(l) à dihydrogen monoxide or water A MOLECULAR COMPOUND can contain what two combinations of elements? Non-­‐metal + non-­‐metal, or non-­‐metal + hydrogen. Name the first 5 PREFIXES that we use to name molecular compounds. mono à one di à two tri à three tetra à four penta à five We usually refer to compounds containing HYDROGEN by their COMMON name. All compounds containing hydrogen are MOLECULAR compounds. How do we indicate the physical state of a compound? (something is written in parentheses; name these things) solid à (s) liquid à (l) gas à (g) aqueous (dissolved in water) à (aq) An IONIC COMPOUND contains what two types of elements? Metal + non-­‐metal (has to be in this order!!!!). How does an atom become an ion? It gains or loses electrons. It becomes a positive ion if it loses electrons, and it becomes a negative ion if it gains electrons. What is used to indicate that an ion has more than one charge (that it is polyatomic)? There are roman numerals written right after the name of the metal. EXAMPLE: iron (II) chloride would be formed using the Fe2+ ion, while iron (III) chloride would be formed using the Fe3+ ion. Name the following examples of IONIC COMPOUNDS (see your notes or textbook to help you): • NaCl(s) à sodium chloride • MgO(s) à magnesium oxide • FeCl2(s) à iron (II) chloride • FeCl3(s) à iron (III) chloride