When you need 8 beats in a note you can tie two whole notes together. A tie can combines the values of the notes.

For six beats you could then use:
A whole note and half note tied.
A dotted whole note.
When ever you can write the value of a note in one note versus two notes you must. So a whole note and a half note would not be acceptable when writing music.

Rests cannot be tied together, they are too restless – couldn’t resist.

Slurs drawn like ties but are used when the note change. Going from a A to B would be a slur. The beats or values would still be combined but the note changes pitch.

Ties and slurs look very similar. To help tell them apart, let's compare and contrast.

1. Ties and slurs are both curved lines that connect notes.

2. Ties only connect notes that have the same pitch.  Slurs connect notes that have different pitches

3. Ties have a rather "flat" curve.  Slurs have a deeper curve, even when they connect pitches that are close together.

4. Though you can have ties in a series, each tie can only connect 2 notes.
Slurs can connect many notes.

5. Ties indicate that two separate notes should be one long sound.
Slurs group notes to indicate articulation. (Identical marks are used to show phrasing.)