Chapter 19
Elements and Their Properties
19.1
Metals
Properties of Metals
• Metals have common properties
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Good conductors of heat and electricity
All but Mercury are solid at room temperature
Reflect light – Luster
Easily hammered/rolled into sheets – Malleable
Easily drawn into wires - Ductile
Ionic Bonding
• Metal atoms have usually 1-3 valence electrons
• Tend to give their electrons up easily
• When they combine with nonmetals, they lose
electrons to the nonmetals, forming ionic bonds
• This makes them more chemically stable
Metallic Bonding
• Occurs among metal atoms
• Positive charged metallic ions are surrounded by
a cloud of electrons
• The electrons move freely among many different
positively charged metal ions
• Explains many properties of metals
• Hammered
• Good conductors
Alkali Metals
• Group one
• Properties
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Shiny
Malleable
Ductile
Softer
Most reactive of all the metals – react
rapidly/violently w/ oxygen and water
• Don’t occur in elemental form in nature – stored in oil
Alkali Metals
• One electron in its outer energy level
• The atom gives up this electron with it combines with
another atom ex. NaCl
• Living things need alkali metals/their compounds
• K, Na, Li
Radioactive Element – one in which the nucleus
breaks down and gives off particles and energy
ex. Francium – very rare & radioactive
Alkaline Earth Metals
• Group 2
• Also not found as free elements in nature –
combine so readily with other elements
• 2 electrons in outer energy level
• These are given up with they combine with
nonmetals and becomes a positively charged ion in a
compound such as CaF2
Alkaline Earth Metals
• Magnesium & Strontium – used in fireworks
• Chlorophyll – Magnesium compound – enables
plants to make food
• Magnesium’s lightness & strength
• Cars, planes, spacecraft
• Household ladders, baseball/softball bats
Alkaline Earth Metals
• Calcium compounds needed for life
• Calcium phosphate – makes bones strong
• Barium compound – swallowed to take x-rays to
diagnose internal abnormalities
• Radium once used to treat cancer
• They now use other readily available radioactive
elements
Transition Elements
• Elements in Groups 3-12
• Often occur in nature as uncombined elements b/c
they are more stable
• Often form colored compounds
Iron, Cobalt, Nickel
• Called the Iron Triad
• Used to create steel/other metal mixtures
• Nickel – added to some metals to make them
stronger or give them a shiny protective coating
• Iron – main component of Steel – most widely
used of all metals
• Second most abundant metallic element in Earth’s
crust (Al is 1st)
Copper, Silver, Gold
• Very stable and malleable
• Found as free elements in nature
• Copper often used in electrical wiring
• Silver compounds – photographs, film
• Silver & Gold – used in jewelry
• Once used to make coins – termed the coinage metals
• Not anymore b/c $$$, most coins now are Ni and Cu
Zinc, Cadmium, Mercury
• Zn, Cd often used to coat other metals
• Cd used in rechargeable batteries
• Hg – silvery, liquid metal
• Used in thermometers, thermostats, switches,
batteries
• Poisonous – can accumulate in body
Inner Transition Metals
• Lanthanides – follow the element lanthanum
• Used with carbon to make compound used to
make movies
• Used to produce color in TV screens
Inner Transition Metals
• Actinides – second row
• Follow the element actinium
• All radioactive and unstable
• Used to make high quality camera lenses, nuclear
reactors, weapons
Questions
1. How is metallic bonding different from covalent
bonding (when two elements share electrons)
2. How would you test something to see if it is a
metal?
3. Why is mercury rarely used in thermometers that
take body temperature?
4. Explain why copper is a good choice for use in
electrical wiring. What type of elements would not
work well for this purpose?
19.2
Nonmetals
Properties of Nonmetals
• Nonmetals – elements that are usually gasses or
brittle solids at room temperature
• Not malleable or ductile
• Most don’t conduct well
• Generally not shiny
• All nonmetals except hydrogen are found to the
right of the stair step line
Bonding in Nonmetals
• Electrons in most nonmetals are attracted to the
nucleus of the atom, so they are poor conductors
• Can form ionic or covalent bonds
• When nonmetals get electrons from metals, they
become the NEGATIVE ions in ionic compounds
• When bonding w/ other nonmetals, usually share
electrons to form covalent compounds
Hydrogen
• 90% of atoms in the universe are hydrogen
• Most on earth found in water
When water is broken down, H becomes a gas made
up of diatomic molecules
Diatomic molecule – 2 atoms of the same element in
a covalent bond
Hydrogen
• Highly reactive
• Single electron – shared when combined with
other nonmetals
• Hydrogen can gain an electron when combining
with alkali and alkaline earth metals to form a
hydride ex. NaH (sodium hydride)
Halogens
• Group 17
• Very reactive in elemental form
• Compounds have many uses
• Fluorides – toothpaste, city water, water to
disinfect
• 7 electrons in outer energy level, so only need 1 to
be HAPPY ☺
Halogens
• If a halogen gains an
electron from a metal,
forms an ionic compound
called a Salt ex. NaCl
• In gas state, halogens
form reactive diatomic
covalent molecules – can
be identified by colors
• Chlorine – greenish yellow
• Bromine – reddish orange
• Iodine - violet
Halogens
• Fluorine – most chemically active of all elements
• Uses of Halogens
• Chlorine compounds – distinct small, most abundant
halogen, used in bleaches to whiten things
• Bromine – only liquid nonmetal at room temp., used
in dyes in cosmetics
• Iodine – shiny solid at room temp, when heated
changes directly to purple vapor – sublimination
• Essential to diet to produce certain hormones
Noble Gases
• Stable
• Outermost energy levels full
Neon and Argon - neon lights
Lightweight helium used in balloons
Argon and Krypton used in electric light bulbs to
produce light in lasers