Answer:

1. Spherical

2. Electrons

Explanation:

In no1. The s (sub shell) can hold a maximum of two electrons as there is only one orbital. S orbitals are spherical in shape and increase in size as the energy level or shell increases.

In no2. In the Bohr model of the atom, electrons travel in defined circular orbits around the nucleus. The orbits are labeled by an integer, the quantum number n. Electrons can jump from one orbit to another by emitting or absorbing energy.