The answer is telophase.
The phase of mitosis when chromosomes attach to the spindle fibers is the metaphase. During metaphase, the chromosomes align along the equatorial plane of the cell before being separated and pulled to opposite poles during anaphase.
Chromosomes attach to the mitotic spindle during the metaphase of mitosis. Part of the answer depends on how you define the stages of mitosis and not everybody does this the same way. The short answer is all of them.
Chromosomes line up at the equator of the spindle during the metaphase stage of mitosis. This is when the chromosomes are maximally condensed and are attached to the spindle fibers at their centromeres.
The first phase in mitosis is prophase, during which the chromosomes condense, the nuclear envelope breaks down, and the mitotic spindle fibers begin to form.
The stage when spindle fibers attach to chromosomes is during metaphase of mitosis or meiosis. Spindle fibers, which are made of microtubules, attach to the centromere region of chromosomes to help separate them correctly during cell division.
During metaphase of mitosis, spindle fibers attach to the centromeres of the sister chromatids and align them at the cell's equatorial plane, also known as the metaphase plate. This positioning is crucial for ensuring that each daughter cell will receive an identical set of chromosomes during the subsequent phase of mitosis.
The phase of mitosis that the nucleus forms is the prophase phase.
The initial visible phase of mitosis is prophase. During prophase, the nuclear envelope breaks down, chromosomes condense, and the mitotic spindle begins to form.
telophase
Prophase
The name for the network of microtubules along which the chromosomes move during cell division is called the spindle fibers. These spindle fibers attach to the chromosomes and pull them in half.
metaphase