CHEM101 Lecture Notes - Lecture 14: Electron Shell, Valence Electron, Metalloid
25 May 2018
School
Department
Course
Professor
CHEM101- Lecture 14
Valences
• Valence electrons- outermost electrons, electrons involved in formation of chemical
bonds between atoms
• Valence shell- outermost shell that is occupied by 1 or more electrons
o n= “shell”
• Noble gas- group 18, completely filled p subshells
o HE- filled s subshell
▪ No 1p orbital
Electron Configuration and Periodic Table
• Group 1 and 2: Main group elements (s & p orbitals)
• Group 3-11: Transition metals
• Group 12 metals
• Group 13-17: Main group
• Group 18: Noble gases
Metals, nonmetals, metalloids
• Elements with similar e- configurations typically have similar chemical properties BUT
must also account for metal, nonmetal, metalloid
o Metalloids- B (boron), Si (silicon), Ge (geranium), As (arsenic), Sb (antimony), Te
(tellurium), Po (polonium)
o N & P- nonmetals, similar properties
o As & Sb- metalloids, similar properties
• Metals- usually solids, shiny (“metallic luster”), malleable, pliable, good conductors of
electricity and heat
o Atoms of main-group metals lose N electrons each, forming N+ ions
o N= Group #
o Na+, Ca2+𝑁𝑎+, 𝐶𝑎2+, 𝐴𝑙2+
• Metalloids- semi-conductors of electricity, useful in electronic components
o Acts like nonmetals
