Chpt 17 Quiz!
1. The currently-accepted model of the atom is
called the _________________?
2. ___________ and ___________ are needed to
determine the atomic mass.
3. How many protons does Bromine have?
4. Which element has two energy levels and five
valence electrons?
5. Atoms of the same element that have different
number of neutrons are called _____________.
6. Atoms are placed on the periodic table in order
of increasing ______________.
7. Quarks are particles of matter that make up
____________ and _____________.
Trends
in the
Periodic Table
Metals
1. ¾ of the elements are metals
• Not all metals are hard
• Ex: Manganese- the metal that isn’t
• It behaves like the transition elements only when
its alloyed with other metals, then it adds strength
and flexibility
2. Shiny (silvery metallic luster)
3. Most are solids at room temperature
4. Good conductors of heat and electricity
5. Malleable- can be flattened into sheets
6. Ductile- can be stretched into wire
7. Can give up valence electrons easily
Group 1
Alkali Metals
• Have similar properties because each has
only one valence electron
• Soft metals
• Extremely reactive- single electron can be
removed easily
•
Ex: if you drop a small piece of an alkali metal into
water, it will react violently as it forms a compound
• Na & K- essential part of our diet
•
Control movement of fluid, transmit nerve impulses,
control muscles
Group 2
Alkaline Earth Metals
• 2 valence electrons- close cousins of the
alkali metal group
•Added electron makes them slightly less
reactive
•Still not found as free elements in nature
•Examples:
•Be- used to harden metal alloys
•Mg- medicinal purposes, fireworks
•Ca- used for structural purposes in people
and buildings
Groups 3-12
Transition Elements
• Sometimes called subgroups- have
either 1 or 2 electrons in the outer shell
•Most have similar properties
•Strong metals
•Iron Triad- iron, cobalt, & nickel
•Common uses: metal mixtures (alloys)
•Sterling silver- copper, silver, gold
•Gold in jewelry- gold, silver, copper
Inner Transition Metals
• The periodic tables usually isn’t shown
with the inner transition elements
positioned where they should be to save
space.
• Lanthanides- atomic #s 58-71
– Uses: produce colors for TV and movies
• Actinides- atomic #s 90-103
– All are radioactive and unstable
– Uses: glass for camera lenses and nuclear
reactors
Nonmetals
1.Hydrogen and the elements on the
right side of the table (17 of them)
2.Hold electrons tightly
• Are more likely to take electrons
from metals than give them up
3.At room temp, most are gases and
some are brittle solids
4.Do not conduct heat and electricity
well
Group 17
Halogens
• Have 7 valence electrons
•Very reactive chemically (WHY???)
•Very distinct properties that change with the
atoms’ size
•As atomic # increases, elements get denser, color
gets darker, phase changes occur
•Very dangerous in strong concentrations
•Chlorine used as poisonous gas in WWI
•Useful in weaker concentrations:
•Cl- kills germs
•F- prevents tooth decay
•I essential nutrient (hyperthyroidism)
Group 18
Noble Gases
•8 valence electrons- outermost
energy level is full!
•Very nonreactive- allows them to
exist in nature as pure substances
•Uses:
•Neon & Argon- neon lights
•Helium- balloons & blimps
•Krypton- light in lasers
Metalloids
1. Have both metallic and nonmetallic
properties
2. A heavy line divides the metals and
nonmetals on the right-hand side of the
table
3. Semiconductors- between a conductor and
an insulator can be controlled
• Without semiconductors, we would not
have watches, pocket calculators, or
microcomputers
Group 13
The Boron Group
• Have 3 valence electrons
•Contains metalloids- elements that have
both metal and nonmetal characteristics
•Can form covalent and ionic bonds
•Ex: Boron
•Aluminum- most abundant metal in
earth’s crust
•Used in pots and pans
Group 14
Carbon Group
• Allotropes- different forms of the same
element (different molecular structures)
• Silicon: occurs as two allotropes
1. A hard, gray substance
2. A brown powder
• Carbon:
1. Diamond- clear and extremely hard
- each carbon atom is bonded to four other
carbon atoms
1. Graphite- a black powder
- Each carbon atom is bonded to three other
carbon atoms
Group 14
Carbon Group
• Have 4 valence electrons
•Few other similarities- Group contains
nonmetals, metalloids, and metals
•Uses:
•Carbon- occurs in coal, oil, natural gas, and foods
•Tin- coat other metals to prevent corrosion
•Included in bronze and pewter alloys
•Lead- used to be used in paint
•Silicon- 2nd most abundant element in Earth’s
crust
•Main component in semiconductors
Group 15
Nitrogen Group
• Have 5 valence electrons
•Elements tend to share electrons
•Make covalent compounds
•Uses:
•Nitrogen- abundant in air and human
bodies
•Phosphorus- fertilizer, match heads
•Antimony & Bismuth- used with other
metals to lower melting points
Group 16
Oxygen Group
• Have 6 valence electrons
•Most share electrons when they bond
•Diatomic molecules- consist of two
atoms of the same element in a covalent
bond
•Uses:
•Oxygen- needed for respiration
•Sulfur- pigments in paint
•Selenium- multivitamins, copy machines