Chapter 6 Study Guide

Section 6.1- Organizing the Elements

Vocabulary: group, period, periodic law, metals, nonmetals, metalloid

History: Mendeleev first arranged the periodic table by increasing atomic mass and was able to use his arrangement to predict properties of undiscovered elements. Once we learned more about the structure of the atom, Henry Moseley arranged the elements by increasing atomic number which gave us the periodic law-when elements are arranged by increasing atomic number, there is a periodic repetition of their properties.

Three classes of elements:

Metals, nonmetals, metalloids- know their placement on the periodic table and their characteristics

Metals- shiny/high luster, good conductors, ductile, solids at room temperature, malleable

Nonmetals- poor conductors, tend to be gases but those that are solids are brittle

Metalloids- properties similar to metals and nonmetals, depends on conditions

Section 6.2- Classifying the Elements

Vocabulary: alkali metals, alkaline earth metals, halogens, noble gases, representative elements, transition metal, inner transition metal

Groups in the periodic table have similar properties because they have the same number of valence electrons. Valence electrons are the outermost electrons in an atom and are those that determine how the atom will react.

Groups:

Alkali metals- most reactive metals, have one valence electron, found in 1A

Alkaline earth metals- have two valence electrons, found in 2A

Halogens- most reactive nonmetals, have seven valence electrons, found in 7A

Noble Gases- inert/unreactive, have completely filled s and p sublevels which makes them very stable, found in 8A

Representative elements

Groups IA-VIIA (1A-7A)

Have partially filled s and p sublevels

Called representative because they display a wide range of properties

Includes alkali metals, alkaline earth metals, and halogens

Transition elements=Group B elements

Transition metals

  • “d block”
  • Metals that we think of as metals; used for jewelry, construction, wiring, etc.
  • Have electrons in s and d sublevel

Inner transition metals

  • “f block”
  • Lanthanide and actinide series
  • Most are radioactive, particularly actinides

Section 6.3- Periodic Trends

Vocabulary: atomic radius, ion, cation, anion, ionization energy, electronegativity

You must know the group and period trends for size, ionization energy, and electronegativity as well as what causes them.

Factors that affect trends (causes): energy level, nuclear charge, shielding

Atomic radius trends

Increase from top to bottom in a group- caused by addition of an energy level and an increase in shielding

Decreases from left to right across a period- caused by increase in nuclear charge

Ions

Formed by losing or gaining electrons

Anion-negative ion formed by gaining electrons, tend to be nonmetals

Cation- positive ion formed by losing electrons, tend to be metals

Ionization energy trends

Decrease from top to bottom in a group- caused by increase in shielding, adding energy levels (the electrons are further away and the attraction of the nucleus is blocked by inner electrons)

Increase from left to right in a period- caused by increase in nuclear charge

Electronegativity trends

Decreases from top to bottom in a group- caused by increase in shielding, adding energy levels

Increases left to right in a period- caused by increase in nuclear charge