Rules for Electron Dot Symbols 1. Representative elements in the same group of the periodic table have the same number of valence electrons 2. The number of valence electrons is represented by “dots” around the symbol of the representative element. 3. The maximum number of valence electrons for any representative element is 8 - Octet Rule.
Learning Check - Aluminum (Al) 1. Number of valence electrons in aluminum is: A) 1 B) 2C) 3 2. In Al, the change in electrons to achieve an octet is: A) loss of 3e - B) gain of 3e - C) a gain of 5e - 3. The Ionic charge of aluminum is: A) 3-B) 5-C) 3 + 4. The symbol for the aluminum ion is: A) Al 3+ B) Al 3- C) Al +
1. Number of valence electrons in sulfur is: A) 4e - B) 6e - C) 8e - 2. Change in electrons for octet requires a: A) loss of 2e - B) gain of 2e - C) a gain of 4e - 3. Ionic charge of sulfur is: A) 2+ B) 2- C) 4- Learning Check
Predicting Ionic Charge The number of electrons an atom loses is related to its position on the periodic table.
The Periodic Table and Ions Group IA metals - +1 Group IIA metals - +2 Group IIIA metals - +3 Group VIIA nonmetals - -1 Group VIA nonmetals - -2 Group VA nonmetals - -3
Chemical Formulas of Ionic Compounds For a neutral species, the number of electrons lost and gained must be equal. The amount of positive charge must equal the amount of negative charge. Formulas of ionic compounds Symbol for the positive ion is always written first The charges on the ions are NOT shown in the formula The subscripts in the formula give the combining ratio for the ions
Lewis Dot Diagrams Using the Electron Dot Symbols, write the Lewis Dot Diagram and the Chemical Formula for Na and Cl
Chapter 4 - Atoms & Elements Periodic Table Symbols for Elements The Atom History Subatomic Particles Atomic Symbols Isotopes, Ions Atomic Mass (amu)
Chapter 5 (Ch4) - Electronic Structure Electromagnetic Radiation Classical vs Quantum History Quantum Numbers Electron Configurations Orbital Diagrams Valence Atomic Radii
Practice Problem The density of diamond is 3.51g/mL. What is the volume (in liters) of the Hope diamond if it has a mass of 44.0 carats? (1 carat = 0.200g)
Practice Multiple Choice 1). Which species has 16 neutrons? a. 31 P b. 34 S 2- c. 36 Cl d. 89 Br - e. none of these (p = 15) (p = 14) (p=17) (p=35) 2). An isotope of which element is used as the standard for the relative mass scale for atoms? a. nitrogen b. oxygen c. hydrogen d. golde. none of these
Practice Multiple Choice 3). Which of the following elements is expected to be chemically similar to calcium (Ca). a. K b. Sc c. Cl d. Mge. Al 4). A g-orbital has an “l” quantum number of 4. How many total electrons can this subshell hold? a. 4b. 6c. 18d. 10e. 14 l = 4, m l = -4,-3,-2,-1,0,1,2,3,4 (9 values = 9 orbitals x 2 = 18 electrons)