The Periodic TableChapter 12
Material on Midterm
Objectives◦ Describe how Mendeleev arranged elements in
the first periodic table◦ Explain how elements are arranged in the modern
periodic table◦ Compare metals, nonmetals, and metalloids base
on their properties and on their location in the periodic table
◦ Describe the difference between a period and a group
Section 1: Arranging the Elements
Placement Pattern◦ What is the best way to arrange things?
Section 1: Arranging the Elements
Discovering a Pattern◦ Mendeleev discovered
that the elements discovered had a pattern to them
Section 1: Arranging the Elements
Mendeleev arranged atoms by increasing atomic mass◦ Saw that there was a periodic trend
Periodic describes something that occurs or repeats at regular intervals
◦ Organized them in a table FIRST PERIODIC TABLE OF THE ELEMENTS Some holes in the table
Section 1: Arranging the Elements
Predicting Properties of Missing Elements◦ Some gaps in the pattern◦ Was able to predict the properties◦ Eka-aluminum….after aluminum
Section 1: Arranging the Elements
Mendeleev’s Predicted Eka-aluminum (1871)
Discovered Germanium (1886)
Atomic mass 70 72.6
Density 5.5 g/cm3 5.3 g/cm3
Appearance Dark gray metal Gray metal
Melting point High melting point 937 C
Changing the arrangement◦ Moseley realized it made more sense to use the
atomic number instead of the atomic mass The periodic law is the law that states that the
repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements
Section 1: Arranging the Elements
The Periodic Table and Classes of Elements◦ We break elements into three major groups
Metals Nonmetals Metalloids
Section 1: Arranging the Elements
Metals◦ Most elements◦ Left of the zigzag line on the periodic table◦ Most are solid at room temperature (Hg
exception)◦ Properties
Shiny Malleable Ductile Good conductors
Section 1: Arranging the Elements
Nonmetals◦ Right of the zigzag line◦ Many are gases at room temperature◦ Not malleable◦ Not ductile◦ Not shiny◦ Poor conductors
Section 1: Arranging the Elements
Metalloids◦ Aka semiconductors◦ Border zigzag line◦ Have some properties of metals◦ Some properties of nonmetals
Section 1: Arranging the Elements
Decoding the Periodic Table
Section 1: Arranging the Elements
Horizontal◦ A period is a horizontal row of elements on the
periodic table◦ Properties repeat as you go along a period
Vertical◦ A group is a vertical column of elements in the
periodic table◦ Elements in a group share chemical properties
Section 1: Arranging the Elements
Section Review◦ Please answer the objectives on your objective
summary sheet
1. Describe how Mendeleev arranged elements in the first periodic table
2. Explain how elements are arranged in the modern periodic table
3. Compare metals, nonmetals, and metalloids base on their properties and on their location in the periodic table
4. Describe the difference between a period and a group
Section 1: Arranging the Elements
Objectives◦ Use the periodic table to gain information about
various elements◦ Explain why elements in a group often have
similar properties◦ Describe the properties of the elements in the
groups of the periodic table
Section 2: Grouping the Elements
We will discuss the following groups:◦ Group 1: Alkali Metals◦ Group 2: Alkaline Earth Metals◦ Groups 3-12: Transition Metals◦ Group 13: Boron Group◦ Group 14: Carbon Group◦ Group 15: Nitrogen Group◦ Group 16: Oxygen Group◦ Group 17: Halogens◦ Group 18: Noble Gases◦ Hydrogen
Section 2: Grouping the Elements
Group 1: Alkali Metals◦ The alkali metals are the elements of
Group 1 of the periodic table (lithium, sodium, potassium, rubidium, cesium, and francium)
◦ Group contains: metals◦ Electrons in outer level: 1◦ Reactivity: Very reactive◦ Other shared properties: softness,
color of silver, shininess, low density
Section 2: Grouping the Elements
Group 2: Alkaline Earth Metals◦ The alkaline earth metals are the
elements of Group 2 of the period table (beryllium, magnesium, calcium, strontium, barium, and radium)
◦ Group contains: metals◦ Electrons in outer level: 2◦ Reactivity: very reactive, but less
reactive than alkali metals◦ Other shared properties: color of silver,
higher densities than alkali metals
Section 2: Grouping the Elements
Groups 3-12: Transition Metals◦ No individual names◦ Varied in properties
◦ Group contains: metals◦ Electrons in outer level: 1 or 2◦ Reactivity: less reactive than the alkaline earth
metals◦ Other shared properties: shininess, good
conductors, higher densities and melting points than Groups 1 and 2 (except Hg)
Section 2: Grouping the Elements
Lanthanides and Actinides◦ The two bottom rows
Row 1: starts with lanthanum--lanthanides Shiny, reactive metals
Row 2: starts with actinium—actinides Radioactive, unstable elements Any after 94—not found naturally
Section 2: Grouping the Elements
Group 13: Boron Group◦ The Boron Group contains elements
from group 13 of the periodic table (boron, aluminum, gallium, indium, and thallium)
◦ Group contains: one metalloid and four metals
◦ Electrons in the outer level: 3◦ Reactivity: reactive◦ Other shared properties: solids at
room temperature
Section 2: Grouping the Elements
Group 14: Carbon Group◦ The carbon group contains elements
from group 14 of the periodic table (carbon, silicon, germanium, tin, lead, flerovium)
◦ Group contains: one nonmetal, two metalloids, and three metals
◦ Electrons in the outer level: 4◦ Reactivity: varies among the elements◦ Other shared properties: solids at
room temperature
Section 2: Grouping the Elements
Carbon: nature’s most important element◦ Found in carbohydrates, proteins, fats, and
nucleic acid (DNA)
Germanium and silicon are used as conductors in computer chips
Section 2: Grouping the Elements
C Si Ge Sn Pb
Group 15: Nitrogen Group◦ The Nitrogen group contains elements
from group 15 of the periodic table (nitrogen, phosphorus, arsenic, antimony, bismuth, ununpentium)
◦ Group contains: two nonmetals, two metalloids, and two metals
◦ Electrons in the outer level: 5◦ Reactivity: varies among the elements◦ Other shared properties: solids at room
temperature (except for nitrogen)
Section 2: Grouping the Elements
Group 16: Oxygen Group◦ The Oxygen group contains elements
from group 16 of the periodic table (oxygen, sulfur, selenium, tellurium, polonium, livermorium {name pending})
◦ Group contains: three nonmetals, one metalloid, and two metals
◦ Electrons in the outer level: 6◦ Reactivity: reactive◦ Other shared properties: all but
oxygen are solid at room temperature
Section 2: Grouping the Elements
Group 17; Halogens◦ The halogens are elements of group 17 of
the periodic table (fluorine, chlorine, bromine, iodine, astatine, ununseptium); halogens combine with most metals to form salts
◦ Group contains: nonmetals◦ Electrons in the other level: 7◦ Reactivity: very reactive◦ Other shared properties: poor conductors,
violent reactions with alkali metals to form salts, never in uncombined form in nature
Section 2: Grouping the Elements
Group 18: Noble Gases◦ The noble gases are elements of group
18 of the periodic table (helium, neon, argon, krypton, xenon, radon, and ununoctium); noble gases are unreactive
◦ Group contains: nonmetals◦ Electrons in the outer level: 8 (except
helium, which has 2)◦ Reactivity: unreactive◦ Other shared properties: colorless,
odorless gases at room temperature
Section 2: Grouping the Elements
Hydrogen◦ The properties of hydrogen do not match
any other group (the loner element)◦ We stick him in group 1 based on outer
electrons
◦ Electrons in outer level: 1◦ Reactivity: reactive◦ Other properties: colorless, odorless gas
at room temperature; low density, explosive reactions with oxygen
Section 2: Grouping the Elements
Section Review◦ Please answer the objectives on your objective
summary sheet
1. Use the periodic table to gain information about various elements
2. Explain why elements in a group often have similar properties
3. Describe the properties of the elements in the groups of the periodic table
Section 2: Grouping the Elements
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