Periods
Seven periods of elements occur naturally on Earth. For period 8, which includes elements which may be synthesized after 2011, see the extended periodic table.
A group in chemistry means a family of objects with similarities like different families.
Read more about this topic: Period (periodic Table)
Famous quotes containing the word periods:
“It has no future but itself—
Its infinite contain
Its past—enlightened to perceive
New periods of pain.”
—Emily Dickinson (1830–1886)
“At great periods you have always felt, deep within you, the temptation to commit suicide. You gave yourself to it; breached your own defenses. You were a child. The idea of suicide was a protest against life; by dying, you would escape this longing for death.”
—Cesare Pavese (1908–1950)
“The History of the world is not the theatre of happiness. Periods of happiness are blank pages in it, for they are periods of harmony—periods when the antithesis is in abeyance.”
—Georg Wilhelm Friedrich Hegel (1770–1831)