Chapter 5.2
Most often there are 4 pieces of information for each element listed on the periodic table. Element Information in the Periodic Table
Atomic mass depends on: __________________ of an element’s isotopes Masses of those isotopes. Isotopes = same element, different masses Masses different because: Same # _______________ Different # ________________ Atomic Mass
Atomic Mass Units Scientists chose one isotope to serve as a standard. This isotope is the most ___________ one found in nature Carbon-12 atom: 6 protons and 6 neutrons. 1 Atomic Mass Unit (_________) = one ________ the mass of a carbon-12 atom. Atomic Mass
Most elements are __________ of 2 or more isotopes. Atomic mass is weighted _______________. Example: Chlorine atomic mass = amu. Two natural isotopes of chlorine: chlorine-35; chlorine-37 Chlorine-35: 17 protons and 18 neutrons. Chlorine-37: 17 protons and 20 neutrons.
Elements in modern periodic table arranged by increasing __________________ (not mass) (Atomic number = # of protons). Periodic Law - Pattern of Repeating Properties Periods - Each __________ is a period. Each period is for a different electron ______ or ____________ level The Periodic Law
Modern periodic table – ____________ out (7 rows) Shows periods with Lanthanide & Actinide series where they really belong The Periodic Law
Elements are also arranged into vertical columns called _____________ (or Families). Sounds of musical notes separated by an octave are related, but they are not identical. Properties of elements in a Group (column) are related, but not identical. Groups - Each column is a Group (or Family). Similar ________________________________ The Periodic Law
Example: Group 8A (or 18) - Noble Gasses with Full Shells Helium - Atomic #2 Neon - Atomic #10 Argon - Atomic #18
The Periodic Law Periodic Table of the Elements
Largest class of elements on the Periodic Table - ___________. _________ of the elements. Metals
Malleable and ductile (can change shape) ______________ = compress without breaking ______________ = stretch without breaking Good Conductors (thermal & electrical) Luster (means they are shiny!) Physical Properties of Metals
Groups 3 – 12: Form a bridge between elements on the left and right side of the table Tough, hard, and strong Less _____________ than standard metals Have more __________ in common than elements in other groups. Transition Metals
Share characteristics of both _____________________. Semi – conductors Metalloids
________________ (poor conductivity) Living organisms are mostly non-metals. (especially C, N, O, H) Most of the compounds in your body contain _________ Non-Metals
Across a period from left to right, the elements become ________ metallic and ______ nonmetallic in their properties. From left to right across Period 3, there are three metals (Na, Mg, and Al), one metalloid (Si), and four nonmetals (P, S, Cl, and Ar). Variations Across a Period
_______________ reacts violently with water. Magnesium will not react with water unless the water is hot. Aluminum does not react with water, but it does react with oxygen. Silicon is generally unreactive. __________________ and sulfur do not react with water, but they do react with oxygen. Chlorine is highly reactive. _____________ hardly reacts at all. Variations Across a Period