in 1962, the Cuban Missile Crisis brought the world to the brink of nuclear war, when the United States discovered that the Soviet Union was attempting to assemble nuclear missiles in Cuba. In 1965, the United States intervened in the Dominican Republic to prevent what it thought was a communist uprising.
Lewis symbols are diagrams that show the number of valence electrons of a particular element with dots that represent lone pairs. Lewis symbols do not visualize the electrons in the inner principal energy levels.
