Final answer:
There is only one sublevel in the first energy level, which is the 1s sublevel. This sublevel can accommodate a maximum of two electrons. It is the lowest energy sublevel filled according to the Aufbau principle, starting with hydrogen's electron configuration of 1s¹.
Step-by-step explanation:
The question How many sublevels are in the first energy level? relates to the concept of electron configurations in chemistry, specifically within quantum theory and atomic structure. The first energy level, also known as the first principal energy level or shell, has only one sublevel, known as the 1s sublevel.
According to quantum theory, electrons within an energy level are organized into sublevels denoted by the letters s, p, d, and f. The number of sublevels within an energy level is determined by the principal quantum number, n, where n corresponds to the energy level number. For the first energy level (n=1), there is just one sublevel, the s sublevel. This sublevel can accommodate two electrons, as denoted by the electron configuration 1s² when full. In the case of hydrogen, its electron would be represented as 1s¹ since hydrogen has only one electron. Thus, in the ground state of an atom, electrons fill the sublevels starting from the lowest energy, with the 1s sublevel being the lowest energy sublevel available to them.
To provide a clear example, for hydrogen and helium, the electrons are configured as follows: hydrogen is 1s¹ and helium is 1s². This pattern of electron filling is guided by the Aufbau principle, which describes the electron filling order from the lowest to the highest energy sublevels.