Question and answer phrases are also known as antecedent and consequent phrases. They can be heard in the opening of the first movement from Mozart’s Symphony No. 40.
Notation of Mozart's first subject
The opening rising bar and a half is answered with the same rhythm, but it falls instead. This way of balancing question and answer phrases is typical of Classical composers.
In the second movement of Haydn’s Symphony No. 101 ‘The Clock’, the first phrase is four bars long and ends with a rising scale (with a chromatic passing note)’. This is ‘answered’ by a similar phrase that is extended by a bar and closes on the tonic. Again, this is typical writing of the period.
Appoggiaturas is used as a dissonance in Classical melodies. To decorate the melody (and harmony) the composer would use an appoggiatura to sound a note outside the chord, which would then fall or rise by step to a note within the chord. The score below shows an appoggiatura from the second movement of Mozart’s Concerto No. 3 for violin. The pink circles show an appoggiatura - the dissonance falls to a consonance.
An acciaccatura is played as quickly as possible before the note that follows it. It is sometimes called a crushed note.
Music from the Classical period is mainly based on the primary chords - I, IV and V, and the secondary chords - II, III, VI and VII.
A seventh is often added to a diminished chord, making it a diminished seventh. If you added a B flat to the chord above, it would be a diminished seventh. The interval between all the notes is a minor third.
All four cadences can be found in Classical music. Perfect and plagal cadences are used to end musical phrases. Imperfect and interrupted cadences are used at the midpoint of phrases as they do not sound ‘complete’, ie the music has to move on before it resolves onto the main chord of the particular key that it is written in.
Haydn’s Symphony No. 101 in D major, ‘The Clock’, is in a major key and uses mainly diatonic chords.
A dominant seventh is used at the end of the phrase before the first time bar. This was typical of a perfect cadence in the Classical period.
Wolfgang Amadeus Mozart, Josef Haydn and Ludwig van Beethoven enjoyed giving a little more harmonic interest to their music by adding chromaticisms. Listen to the opening of Beethoven’s Piano Sonata no.8 in C minor, ‘The Pathetique’. Beethoven’s use of the diminished chord adds drama and tension to the music.
In the Classical period, composers used modulations to help provide contrast between key musical ideas or sections within their pieces. For example, if the first key melody was in the tonic key, the second key melody might be in the dominant key.
In common musical forms of the Classical period, such as sonata form, modulations to the dominant, subdominant and relative minor keys are all fairly common in the development section, ie the section after the exposition. The exposition is where the key ideas of the music are introduced.
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.
Classical era music: a beginner's guide
http://www.classicfm.com/discover-music/periods-genres/classical/classical-music-beginners-guide/
The Classical Era, Classical Forms and Symphony, J. Haydn
Classical Opera and Choral Music, W. A. Mozart
Classical Instrumental and Chamber Music, L. Beethoven
Genius of Beethoven (Documentary on Youtube)
https://www.youtube.com/watch?v=Z705H2c8cto
Famous Classical Music Composers Linked to YouTube Videos...