Chapter 5.2 – Exploring the Periodic Table periodic trends on the periodic table are due to electron arrangement the number of valence electrons determines chemical properties an elements location is related to its electron arrangement s p sublevel being filled d f

Chapter 5.2 – Exploring the Periodic Table Group 1 and 2 fill the s sublevel Group 1 has 1 valence electron Group 2 has 2 valence electrons Groups 13 – 18 fill the p sublevel, the s sublevel is filled Group 13 has 3 valence electrons Group 14 has 4 valence electrons Group 15 has 5 valence electrons Group 16 has 6 valence electrons Group 17 has 7 valence electrons Group 18 has 8 valence electrons

Chapter 5.2 – Exploring the Periodic Table ion – atom or molecule that has gained or lost one or more electrons and has a negative or positive charge ions do not have equal numbers of protons and electrons atoms want to fill their s and p sublevels and have 8 valence electrons atoms gain 8 valence electrons by gaining or losing electrons cation – positive ion anion – negative ion

Chapter 5.2 – Exploring the Periodic Table if an atom has 1, 2, or 3 valence electrons, the atom will lose electrons and form a positive ion if an atom has 5, 6, or 7 valence electrons, the atom will gain electrons and form a negative ion Lithium (Li) – Group 1 – has 1 valence electron – forms Li+ ion Oxygen (O) – Group 16 – 6 valence electrons – forms O2- ion

Chapter 5.2 – Exploring the Periodic Table metal – element that is shiny and conducts heat and electricity well - found on the left side of the periodic table - most elements are metals nonmetal – element that conducts heat and electricity poorly - found on the right side of the periodic table - most are gases

Chapter 5.2 – Exploring the Periodic Table semiconductor or metalloid – element that conducts electric current better than an insulator but not as well as a conductor - shares properties with metals and nonmetals - found between metals and nonmetals on the periodic table