Elements and the Periodic Table
Properties – characteristics or how an element looks or acts.
Examples: density (hollow/not hollow), appearance, melting point, boiling point, atomic mass
Element – a pure substance that cannot be separated into simpler substances by physical or chemical means.
Dmitri Mendeleev discovered a pattern to the elements in 1869.
Mendeleev arranged the elements in order of increasing atomic mass.
Periodic – when something occurs or repeats at regular intervals.
Periodic Table of the Elements – Mendeleev’s table which shows elements’ properties following a pattern that repeats every seven elements.
A few elements’ properties did NOT fit the pattern in Mendeleev’s table.
Henry Moseley determined the atomic number for each element.
Once arranged by atomic number, all elements fit the pattern in Mendeleev’s table.
Periodic Law – when the repeating chemical and physical properties of elements change periodically with the elements’ atomic numbers.
Elements are classified as metals, nonmetals, or metalloids according to their properties (characteristics).
The zigzag line on the periodic table reminds you where the metals, nonmetals and metalloids are.
The background color tells the type of element (metal, metalloid, nonmetal).
Most elements are metals.
Metals are found to the left of the zigzag line.
Most metals are solid at room temperature.
Metals tend to be shiny.
Most metals are ductile.
Ductile – can be drawn into thin wires.
Most metals are malleable.
Malleable – can be flattened with a hammer and will not shatter.
Most metals are good conductors of thermal energy.
Nonmetals are found to the right of the zigzag line.
Many nonmetals are gases at room temperature.
Nonmetals are dull (not shiny).
Nonmetals are brittle.
Nonmetals are poor conductors of thermal energy and electric current.
Metalloids are the elements that border the zigzag line on the periodic table.
Metalloids also called semiconductors.
Metalloids have properties of metals and of nonmetals.
Look at the periodic table on page 108.
Each square of the periodic table contains information on one element.
The Atomic number is the top number in each element box.
The Atomic mass is the bottom number in each element box.
The colored letter(s) in the middle of the box is the Chemical Symbol.
Most elements' chemical symbol has one or two letters with the first letter always capitalized.
The color of the chemical symbol tells the physical state (solid, liquid, gas) of the element at room temperature.
The word under the chemical symbol is the Element name.
Some elements are named after scientists (Mendelevium).
Some elements are named after places (Californium).
Period – a horizontal row of elements in the periodic table.
Properties such as reactivity change gradually from left to right in each period.
Reactivity – an elements’ tendency to easily participate in a reaction.
Group or Family – a vertical column of elements in the periodic table.
Elements in the same group or family often have similar chemical and physical properties.
Source: http://www.mpsaz.org/fremont/staff/mmrowell/my_science_calendar/files/elements_and_the_periodic_table_key.doc
Web site to visit: http://www.mpsaz.org
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