Scope, Sequence, and Coordination

A Framework for High School Science Education

Based on the National Science Education Standards


Patterns Using Metals, Nonmetals and Metalloids

Elements, Atoms, and the Periodic Table
An element is composed of a single type of atom. When elements are listed in order according to the number of protons (called the atomic number), repeating patterns of physical and chemical properties identify families of elements with similar properties. This APeriodic Table@ is a consequence of the repeating pattern of outermost electrons and their permitted energies.


Further Description:

Elements can be grouped or classified according to their physical and chemical characteristics (metals, nonmetals, and metalloids). Early chemists grouped elements with very similar properties into families. These families could be arranged into a pattern called the periodic table. Each element is composed of a single type of atom containing a specific number of protons and an equal number of electrons.

When elements are listed in ascending order of the number of protons, the periodic table is seen to be a consequence of a repeating pattern of outermost electrons. Other atomic properties also follow patterns, including atomic size, ionic size, ionization energies, electron affinity, and electronegativity. Detailed electron configurations of atoms are also reflected in the periodic table and explain variations between closely related elements.


Concepts Needed:

Grade 9

Chemical family, periodic table, metal, nonmetal, metalloid

Grade 10

Valence electron, proton, neutron, atomic number, atomic mass number, isotope

Grade 11

Atomic size, ionic size, ionization energy, electronegativity, electrode potential, isotope, periodicity

Grade 12

Energy level, sublevel, orbital electron spin, electron affinity, electron configuration


Empirical Laws or Observed Relationships:

The periodic law


Theories or Models:

Atomic theory


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Micro-Unit Description:

Patterns Using Metals, Nonmetals and Metalloids
Students should learn that early chemists grouped elements with similar properties into families. These families could be arranged into a pattern called the periodic table. Students should classify or group elements according to their physical and chemical characteristics (metals, nonmetals, metalloids) and learn the names of common elements and their symbols. This should be done in conjunction with direct observation of samples of the various common elements whose symbols are being learned. Thus students should look at samples, touch them when safe to do so, and consider their appearance, density, and other measurable observable properties, so that the symbol for the element represents something common to their experience.


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