Atoms, Elements, and the Periodic Table Ch. 17 & 19 Ch. 17 Section 3 The Periodic Table Warm Up Draw the Bohr Model for sodium What word can you make using the symbols for the elements sulfur, oxygen, carbon, and potassium? The Periodic Table Atoms are organized into an arrangement of elements called the periodic table The elements are ordered by increasing atomic number, or number of protons The Periodic Table Elements are arranged by physical and chemical properties The Periodic Table Vertical columns are called Groups Groups are numbered from 1 to 18 Elements in each group have the same number of electrons in their outer energy level The Periodic Table Each period starts with an atom with one electron in the outer energy level and ends with an atom that has a full outer energy level Each row is called a period The Periodic Table Elements in the first period on the periodic table have electrons in the first energy level Elements in the second period have electrons in their first and second energy levels The Periodic Table Elements of the same group have the same number of electrons in their outer energy level An electron dot diagram, or Lewis Structure, uses the symbol of the element and dots to represent the electrons in the outer energy level only Fill in the Lewis Structures below: O Xe Li The Periodic Table Electron dot diagrams of group 1 would all have 1 electron in their outer energy level Electron dot diagrams of group 17 would all have 7 electrons Fill in the lewis structures on the right Na Br Periodic Table The Periodic Table has 3 main sections of elements with similar properties: Metals Nonmetals Metalloids Metals Properties of metals include: Conduct heat & electricity Solid at room temperature (all except Hg) Reflective, malleable, ductile Metals Metals generally have 1-4 electrons in the outer energy level (valence electrons) Metals typically give up these electrons to other atoms Alkali Metals Group 1 contains elements that have 1 valence electron These elements are called the Alkali Metals, and are the most reactive metals Alkaline Earth Metals Group 2 contains elements with 2 valence electrons These elements are called the Alkaline Earth Metals and are also very reactive Transition Elements Groups 3-12 are the more stable Transition Elements They usually exist uncombined with other elements because they are not as reactive Inner Transition Elements The disconnected rows underneath the rest of the table are the Inner Transition Elements They fit between groups 3 & 4 in periods 6 & 7 Inner Transition Elements The first row contains the Lanthanides, named because they follow Lanthanum The second row contains the Actinides, named because they follow Actinium The actinides are radioactive and unstable because the large number of protons repel each other Nonmetals Properties of nonmetals: Usually gases or brittle solids at room temp. Not malleable or ductile Not usually conductive or reflective Nonmetals Hydrogen is a nonmetal H atoms have a single electron, so it can share its electron with other atoms like oxygen Nonmetals Group 17 on the periodic table contains the halogens Atoms of these elements have 7 electrons in their outer energy level and need only one more to complete it Halogens are very reactive Nonmetals The noble gases are in group 18 of the periodic table They are stable because their outer energy levels are full Mixed Groups Metalloids have properties of metals and nonmetals Groups 13, 14, 15, and 16 contain metalloids Mixed Groups The Boron Group, group 13, contains: Boron, a metalloid Aluminum and other metals The Carbon Group, group 14 contains: Carbon, a nonmetal Silicon and germanium, metalloids Tin and lead, metals Elements all have 4 valence electrons Mixed Groups Group 15, the Nitrogen Group, contains: Nitrogen and phosphorus, nonmetals Arsenic and antimony, metalloids Bismuth, a metal Elements with 5 valence electrons Group 16, the Oxygen Group, contains: Oxygen, sulfur, and selenium nonmetals Tellurium and polonium, metalloids Elements with 6 valence electrons