Transcript Chapter 19 - murraysphysical

Chapter 19
Elements and Their Properties
Metals

Properties of Metals
– Conduct heat and electricity.
– Luster- reflect light well.
– Malleable- can be hammered or rolled
into sheets.
– Ductile- can be drawn into wires.
Metals- Cont.
– Ionic Bonds- combine
with nonmetals by
losing electrons.
Metals- Cont.
– Metallic Bonds- positively charged metallic
ions are surrounded by a cloud of electrons;
ions are in sliding layers and electrons are
weakly held; readily form ionic bonds with
nonmetals.
Alkali Metals

The Alkali Metals- softer and
more reactive than other
metals.
– Highly reactive with oxygen and
water; don’t occur naturally in
elemental forms.
– Combine readily with other
elements due to single
electrons in the outer energy
level.
Alkali Metals are
found in Group 1 of
the Periodic Table.
Alkali Metals- Cont.
- Multiple uses
– Human Health- Na, K, Li
– Photocells- some depend on Ru or Cs
– Francium- a radioactive element which breaks
down giving off particles and energy
Alkaline Earth Metals

Alkaline Earth Metals- not found naturally
in elemental form; two electrons in outer
energy level.
Alkaline Earth Metals
are found in Group 2
of the Periodic Table.
Alkaline Earth Metals
– Applications- Strontium and Magnesium found in
fireworks; Magnesium in vehicles, ladders, and
bats; Calcium in statues and countertops
– Human body- Calcium in
bones; Barium in disease
diagnoses; Radium
formerly used in cancer
treatment
Transition Metals

Transition Metals- they often occur in
nature as uncombined elements
Transition Metals are
found in Groups 3-12
of the Periodic Table.
Transition Metals- Cont.
– Typically form colored
compoundsChromium found in
rubies and emeralds
Chromium in it’s raw form.
Transition Metals- Cont.
– Iron Triad- Iron, Cobalt, and Nickel
 Iron- Most widely used of all metals and main
ingredient in steel; abundant in Earth’s crust
 Cobalt & Nickel- used in some steels
 Nickel used to coat other metals
Transition Metals- Cont.
– Copper, silver, gold- Coinage metals since
once were commonly used in coins
 Copper- used in electric wiring because it is a
superior electricity conductor.
 Silver- used in photographic film and paper,
jewelry
 Gold- used in jewelry and fillings
Transition Metals- Cont.
– Zinc, Cadmium, Mercury- Group 12 on the
periodic table
 Zinc & Cadmium- often used to coat or plate other
metals
 Mercury- only room temperature liquid metal; used
in thermometers and batteries
Transition Metals- Cont.
– Inner transition- seem disconnected from the
rest of the periodic table
 Lanthanides- include La, Cr, Pr, Sm, Eu, Gd, Tb
 Actinides- all are radioactive and unstable;
Uranium is the best known
Uranium in raw form.
Nonmetals

Properties of Nonmetals
Usually gases or brittle solids at room
temperature
Are not malleable or ductile
Usually poor conductors of heat and electricity
Usually not lustrous
Non Metals- Cont.
– Ionic compounds form when nonmetals gain
electrons from metals and become negative
ions.
– Covalent compounds form when nonmetals
share electrons with other nonmetals.
Nonmetals- Cont.

Hydrogen- most common
element in universe
– Diatomic molecule- two
atoms of the same element
in a covalent compound
– Highly reactive element
found mostly on Earth as
part of a water compound
Nonmetals- Cont.

Halogens- include Bromine, Iodine,
Fluorine, Chlorine, and Astatine
Halogens are found in
group 17 of the
periodic table.
Nonmetals- Cont.
– A salt forms when a halogen gains one
electron from a metal
– Uses of Halogens
 Chlorine- disinfectant and bleach
 Bromine- dyes in cosmetics
 Iodine- hormone regulation
– Sublimation- a solid changes directly into a
gas without first becoming a liquid
Nonmetals- Cont.

Noble Gases- exist as isolated, stable
atoms
– Helium- used in blimps and balloons
– Neon, Argon, Krypton- used in lights
Review Question
C12 H22 O11
Number of atoms
 C=
 H=
 O=


Total number of atoms:________
Mixed Groups

Properties of Metalloids
Form ionic and covalent bonds
Have some metallic and some nonmetallic
properties
Partial conduction gives them semiconductor
characteristics
Mixed Groups- Cont.

Boron Group- named for the first element
in Group 13
– Boron- use in water softening products,
antiseptic, and fuels
– Aluminum- abundant in Earth’s crust; used in
cans, foil wrap, pans, building materials, and
aircraft
Mixed Groups- Cont.

Carbon Group- four electrons in outer energy
level
– Carbon- found in coal, oil, natural gas, and foods
– Silicon occurs as an allotrope- same element with
different molecular structures
 Silicon- found in sand, rocks, and soil
 The main component in semiconductors, which conduct
electricity under certain conditions
–
–
–
–
Germanium- also used in semiconductors
Tin- used to coat other metals
Lead- toxic, so no longer used in paint
Diamonds, graphite, and buckminsterfullerene are all
allotropes of carbon.
Mixed Groups- Cont.

Nitrogen Group- five electrons in outer
energy level; trend to form covalent bonds
– Nitrogen- used to make nitrates and ammonia
– Phosphorus- used in water softeners,
fertilizers, match heads, fine china
– Antimony and Bismuth- used with other
metals to lower melting points
Mixed Groups- Cont.

Oxygen or Group 16
– Oxygen- makes up 20% of air, is used by
living things in respiration, and provides
protection from the sun’s radiation
– Sulfur- used to form sulfides for pigment in
paint
– Selenium- used in photocopiers and
multivitamins
– Te & Po are also oxygen group elements.
Mixed Groups- Cont.

Synthetic elements- scientists create elements
not usually found on Earth; synthetic elements
usually disintegrate quickly
– Uranium can be made into Neptunium which forms
plutonium when it disintegrates
– Plutonium can be changed into Americum, which is
used in smoke detectors.
– Transuranium have more than 92 protons and are
synthetic and unstable
 The study of synthetic elements helps scientists to
understand the forces holding the nucleus together.
 Element 114 lasted for 30 seconds.
 It combined 114 protons with 175 neutrons.
 It broke apart due to enormous repulsion between the
protons.