The Periodic Table of Elements

What are atoms?  Atoms are composed of protons, electrons, and neutrons. The number of protons in the nucleus of an atom is equal to its atomic number.  In the ground state, the number of protons equals the number of electrons. It also equals the number of neutrons.  Protons = Neutrons = Electrons

What is the Periodic Table of the Elements?  Elements are substances that cannot be broken down any further by chemical means.  The Periodic Table is the arrangement of these elements by increasing atomic number and similar properties.

Properties  Chemical- A property used to characterize materials in reactions that change their identity. Ex: electronegativity, pH, toxicity, reactivity, flammability  Physical- A characteristic of a substance that can be observed without changing the substance into something else. Ex: length, color, shape, density, mass, volume, solubility,

How is it specifically arranged?  Periods (Rows)  Groups (Columns)  Atomic number

Periods Row = Period Period Number = Highest Unexcited Energy Level Why are there more elements in a period as you move down the periodic table?

Groups Column = Group Share Number of Valence Electrons and Common Properties What is a valence shell? Outermost Shell Same Valence Electrons = Similar Chemical Properties Roman Numerals = Valence Electrons Fluorine (F) –  Roman Numeral VII  7 valence electrons

Properties and Trends  Properties in Comparison Atom Size Energy Required to Remove an Electron from an Atom Ability to Form a Chemical Bond

Organizing Elements  Elements are sorted by common properties.  The major categories of elements are the metals, nonmetals, and metalloids.

Metals  What is a metal? Metals are lustrous, malleable, and are good conductors of heat and electricity. This is because the electrons in the valence shell of a metal has electrons that move easily.

What are the types of metals?  Alkali Metals  Alkaline Earth Metals  Transition Metals

Nonmetals  Elements that do not share the properties of metals.  Halogens  Noble Gases

Metalloids (Semimetals)  Elements that share some, but not all the properties of metals.  Staircase

State  The three states of matter are solid, liquid, and gas.  Most elements are solid at standard temperature, but a few are gaseous and only a couple are liquid.  Noble gases are all gaseous at standard temperature.

Atomic Mass  How heavy an atom is.  Calculated by adding up the masses of the protons, neutrons, and electrons of an atom.

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