Around mid-century, Mendeleev began to develop the table of elements which helped in the discovery of new elements. In the last decade of the century, the discovery of radium by Marie and Pierre Curie, and the electron by Becquerel as well as observation of radioactivity in the laboratory, challenged Dalton's theory.
Medications Used to Treat ADHD. Stimulant medications commonly prescribed for attention deficit disorder include methylphenidate (Ritalin, Concerta, Metadate, Methylin) and certain amphetamines (Dexedrine, Dextrostat, Adderall). Methylphenidate is a short acting drug, and in older forms, had to be taken multiple times a day.
1 Methylphenidate (such as Concerta or Ritalin) is often the first choice for treating ADHD. 2  Dextroamphetamine or the combination dextroamphetamine and amphetamine (Adderall) is usually the second choice when the person does not improve with methylphenidate.3  But either may be the preferred medicine for older children.ost of the medicines used to treat ADHD come with a U.S. Food and Drug Administration (FDA) warning about possible heart-related or mental problems. Before starting a medicine for ADHD, tell your doctor if your child or you have any heart problems, heart defects, or mental health problems.