Prelude in D flat major Op.28, Section A, by Frederic Chopin
In Symphonie Fantastique, Berlioz uses an idée fixe to frame and structure the movements. This musical idea appears in different forms. At the beginning, it appears as a poet’s thought of his beloved as an ideal. Later on the idea changes into a nightmarish vision of his beloved taking part in the witches’ Sabbath.
Composers added chromatic notes to their chords and melodies to make their music more expressive. In the slow movement of Sergei Rachmaninov’s Piano Concerto No. 2, the opening flute melody contains chromatic notes as well as accompanying chords. These dissonances usually resolve to consonant chords - or diatonic chords - which creates a feeling of tension and release.
Extended chords are chords which have extra notes – through adding thirds on top of the seventh, ninth, eleventh, thirteenth etc. Extended chords were frequently used by Claude Debussy.
Structures and forms that were established in the Baroque period were developed into longer and more complex structures during the Classical and Romantic periods. As melodies and phrases became longer, so did individual sections.
Sonata form was a new structure that evolved from the Baroque forms of the Classical period. It was usually the form of the first movement of sonatas, symphonies and concertos.
Sonata form has three main sections - exposition, development and recapitulation. Most of the musical ideas come from two main themes known as the first and second subject.
In the exposition the material is 'exposed' - or presented for the first time. There are two main melodies known as the first and second subject.
The first movement of Mozart’s Symphony No. 40 is in sonata form.
In the Romantic period, composers further developed sonata form. Instead of modulating to the dominant, composers would choose keys which were less related). Sections were much longer in the Romantic period, with development sections modulating to more distant keys as well.
The cadenza is a section found in the Classical concerto. It is a brilliant dramatic solo passage where the soloist plays, and the orchestra pauses and remains silent.
The cadenza:
The minuet and trio was often found in symphonies as an additional third movement, which came before the final movement. The minuet and trio originated from the Baroque dance form. The overall form of the minuet and trio is ternary, but within each section there is usually binary form. After the trio, the minuet returns but without the repeats:
Rondo form evolved from the Baroque ritornello form and was often found as the final movement in a symphony, sonata or concerto. Section A returns in related keys.
Romantic Period Lessons from Study.com
http://study.com/academy/topic/the-romantic-period-in-music-lesson-plans.html