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